SCHEDULE 13G

Amendment No. 0 
21VIANET GROUP INC 
Common Stock 
Cusip #90138A921 


Cusip #90138A921 
Item 1:	Reporting Person - FMR LLC
Item 4:	Delaware
Item 5:	11,120,850 
Item 6:	0 
Item 7:	18,847,476 
Item 8:	0 
Item 9:	18,847,476 
Item 11:	10.413% 
Item 12:	    HC


Cusip #90138A921  
Item 1:	Reporting Person - Edward C. Johnson 3d 
Item 4:	United States of America
Item 5:	0 
Item 6:	0 
Item 7:	18,847,476 
Item 8:	0 
Item 9:	18,847,476 
Item 11:	10.413% 
Item 12:	IN 




	SCHEDULE 13G - TO BE INCLUDED IN 
STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)



Item 1(a).	Name of Issuer:	

		21VIANET GROUP INC 

Item 1(b).	Name of Issuer's Principal Executive Offices:

		M5, 1 Jiuxianqiao East Rd
		Chaoyang District 
		Beijing F4 100016
		China  

Item 2(a).	Name of Person Filing: 

		FMR LLC

Item 2(b).	Address or Principal Business Office or, if None, 
Residence:

		82 Devonshire Street, Boston, 
Massachusetts  02109

Item 2(c).	Citizenship:

		Not applicable

Item 2(d).	Title of Class of Securities:

		Common Stock 

Item 2(e).	CUSIP Number:  

		90138A921 

Item 3.	This statement is filed pursuant to Rule 13d-1(b) or 13d-2(b) 
and the person filing, FMR LLC, is a parent holding company 
in accordance with Section 240.13d-1(b)(ii)(G).  (Note:  See 
Item 7).

Item 4.	Ownership

	(a)	Amount Beneficially Owned:	18,847,476 

	(b)	Percent of Class:	10.413% 

	(c)	Number of shares as to which such 
person has:  

	(i)	sole power to vote or to direct 
the vote:	11,120,850 

	(ii)	shared power to vote or to 
direct the vote:	0 

	(iii)	sole power to dispose or to 
direct the disposition of:	18,847,476 

	(iv)	shared power to dispose or to 
direct the disposition of:	0 



Item 5.	Ownership of Five Percent or Less of a Class.

	Not applicable.

Item 6.	Ownership of More than Five Percent on Behalf of Another 
Person.

	Various persons have the right to receive or the power to 
direct the receipt of dividends from, or the proceeds from the 
sale of, the Common Stock of 21VIANET GROUP INC.  No 
one person's interest in the Common Stock of 21VIANET 
GROUP INC is more than five percent of the total outstanding 
Common Stock.

Item 7.	Identification and Classification of the Subsidiary Which 
Acquired the Security Being Reported on By the Parent 
Holding Company.

	See attached Exhibit A. 

Item 8.	Identification and Classification of Members of 
the Group.

	Not applicable.  See attached Exhibit A. 

Item 9.	Notice of Dissolution of Group.

	Not applicable.

Item 10.	Certifications. 

	By signing below I certify that, to the best of my knowledge 
and belief, the securities referred to above were acquired in the 
ordinary course of business and were not acquired for the 
purpose of and do not have the effect of changing or 
influencing the control of the issuer of such securities and 
were not acquired in connection with or as a participant in any 
transaction having such purpose or effect.  I also certify that, 
to the best of my knowledge and belief, FIL Limited and its 
various non-U.S. investment management subsidiaries 
included on this Schedule 13G are subject to a regulatory 
scheme substantially comparable to the regulatory scheme 
applicable to the functionally equivalent U.S. institutions.  I 
also undertake to furnish to the Commission staff, upon 
request, information that would otherwise be disclosed in a 
Schedule 13D with respect to FIL Limited and its various non-
U.S. investment management subsidiaries included on this 
Schedule 13G. 

Signature

	After reasonable inquiry and to the best of my knowledge and 
belief, I certify that the information set forth in this statement 
is true, complete and correct. 

October 09, 2012 			
Date

 /s/ Scott C. Goebel			
Signature

Scott C. Goebel				
Duly authorized under Power of Attorney
effective as of June 1, 2008 by and on behalf of FMR LLC 
and its direct and indirect  subsidiaries


	SCHEDULE 13G - TO BE INCLUDED IN 
STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)



	Pursuant to the instructions in Item 7 of Schedule 13G, 
Fidelity Management & Research Company ("Fidelity"), 82 
Devonshire Street, Boston, Massachusetts 02109, a wholly-
owned subsidiary of FMR LLC and an investment adviser 
registered under Section 203 of the Investment Advisers Act 
of 1940, is the beneficial owner of 7,726,626 shares or 4.269% 
of the Common Stock outstanding of 21VIANET GROUP 
INC  ("the Company") as a result of acting as investment 
adviser to various investment companies registered under 
Section 8 of the Investment Company Act of 1940.

	Edward C. Johnson 3d and FMR LLC, through its 
control of Fidelity, and the funds each has sole power to 
dispose of the 7,726,626 shares owned by the Funds.

	Members of the family of Edward C. Johnson 3d, 
Chairman of FMR LLC, are the predominant owners, directly 
or through trusts, of Series B voting common shares of FMR 
LLC, representing 49% of the voting power of FMR LLC.  
The Johnson family group and all other Series B shareholders 
have entered into a shareholders' voting agreement under 
which all Series B voting common shares will be voted in 
accordance with the majority vote of Series B voting common 
shares.  Accordingly, through their ownership of voting 
common shares and the execution of the shareholders' voting 
agreement, members of the Johnson family may be deemed, 
under the Investment Company Act of 1940, to form a 
controlling group with respect to FMR LLC.

	Neither FMR LLC nor Edward C. Johnson 3d, 
Chairman of FMR LLC, has the sole power to vote or direct 
the voting of the shares owned directly by the Fidelity Funds, 
which power resides with the Funds' Boards of Trustees.  
Fidelity carries out the voting of the shares under written 
guidelines established by the Funds' Boards of Trustees.

	Pyramis Global Advisors, LLC ("PGALLC"), 900 
Salem Street, Smithfield, Rhode Island, 02917, an indirect 
wholly-owned subsidiary of FMR LLC and an investment 
adviser registered under Section 203 of the Investment 
Advisers Act of 1940, is the beneficial owner of 413,400 
shares or 0.228% of the outstanding Common Stock of 
21VIANET GROUP INC as a result of its serving as 
investment adviser to institutional accounts, non-U.S. mutual 
funds, or investment companies registered under Section 8 of 
the Investment Company Act of 1940 owning such shares.

	Edward C. Johnson 3d and FMR LLC, through its 
control of PGALLC, each has sole dispositive power over 
413,400 shares and sole power to vote or to direct the voting 
of 413,400 shares of Common Stock owned by the 
institutional accounts or funds advised by PGALLC as 
reported above.

	FIL Limited ("FIL"), Pembroke Hall, 42 Crow Lane, 
Hamilton, Bermuda, and various foreign-based subsidiaries 
provide investment advisory and management services to a 
number of non-U.S. investment companies and certain 
institutional investors.  FIL, which is a qualified institution 
under section 240.13d-1(b)(1)(ii), is the beneficial owner of 
10,707,450 shares or 5.916% of the Common Stock 
outstanding of the Company.

	Some or all of the shares of Common Stock of 
21VIANET GROUP INC owned by the investment companies 
at September 30, 2012 may include shares represented by 
American Depository Shares.

	Partnerships controlled predominantly by members of 
the family of Edward C. Johnson 3d, Chairman of FMR LLC 
and FIL, or trusts for their benefit, own shares of FIL voting 
stock. While the percentage of total voting power represented 
by these shares may fluctuate as a result of changes in the total 
number of shares of FIL voting stock outstanding from time to 
time, it normally represents more than 25% and less than 50% 
of the total votes which may be cast by all holders of FIL 
voting stock. FMR LLC and FIL are separate and independent 
corporate entities, and their Boards of Directors are generally 
composed of different individuals.

	FMR LLC and FIL are of the view that they are not 
acting as a "group" for purposes of Section 13(d) under the 
Securities Exchange Act of 1934 (the "1934" Act) and that 
they are not otherwise required to attribute to each other the 
"beneficial ownership" of securities "beneficially owned" by 
the other corporation within the meaning of Rule 13d-3 
promulgated under the 1934 Act.  Therefore, they are of the 
view that the shares held by the other corporation need not be 
aggregated for purposes of Section 13(d). However, FMR 
LLC is making this filing on a voluntary basis as if all of the 
shares are beneficially owned by FMR LLC and FIL on a joint 
basis.

	FIL has sole dispositive power over 11,899,650 shares 
owned by the International Funds. FIL has sole power to vote 
or direct the voting of 10,707,450 shares and no power to vote 
or direct the voting of 0 shares of Common Stock held by the 
International Funds as reported above.


	SCHEDULE 13G - TO BE INCLUDED IN 
STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)
	RULE 13d-1(f)(1)  AGREEMENT

	The undersigned persons, on October 09, 2012, agree 
and consent to the joint filing on their behalf of this Schedule 
13G in connection with their beneficial ownership of the 
Common Stock of 21VIANET GROUP INC at September 30, 
2012.

	FMR LLC

	By /s/ Scott C. Goebel			
	Scott C. Goebel
	Duly authorized under Power of Attorney effective as 
of June 1, 2008, by and on behalf of FMR LLC and its direct 
and indirect subsidiaries

	Edward C. Johnson 3d

	By /s/ Scott C. Goebel			
	Scott C. Goebel
	Duly authorized under Power of Attorney effective as 
of June 1, 2008, by and on behalf of Edward C. Johnson 3d

	Fidelity Management & Research Company

	By /s/ Scott C. Goebel			
	Scott C. Goebel
	Senior V.P. and General Counsel

	FIL Limited

	By /s/ Scott C. Goebel			
	Scott C. Goebel
	Duly authorized under Power of Attorney
	effective as of June 1, 2008, by and on behalf 
	of FIL Limited and its direct and indirect 
	subsidiaries