SCHEDULE 13G
 
Amendment No. 2
21VIANET GROUP INC
CLASS A COMMON STOCK
Cusip #90138A921
Check the appropriate box to designate the rule pursuant to which this 
Schedule is filed:
[x] 	  Rule 13d-1(b)
[ ] 	  Rule 13d-1(c)
[ ] 	  Rule 13d-1(d)
Cusip #90138A921
Item 1: 	   	Reporting Person - FIL Limited
Item 2: 	   	(a)  	[ ]
   	   	(b)  	[ ]
Item 4: 	   	Bermuda
Item 5: 	   	15,812,820
Item 6: 	   	0
Item 7: 	   	28,954,248
Item 8: 	   	0
Item 9: 	   	28,954,248
Item 11: 	   	8.386%
Item 12: 	   	FI
Cusip #90138A921
Item 1: 	   	Reporting Person - Pandanus Partners, L.P.
Item 2: 	   	(a)  	[ ]
   	   	(b)  	[ ]
Item 4: 	   	Delaware
Item 5: 	   	0
Item 6: 	   	0
Item 7: 	   	28,954,248
Item 8: 	   	0
Item 9: 	   	28,954,248
Item 11: 	   	8.386%
Item 12: 	   	PN
Cusip #90138A921
Item 1: 	   	Reporting Person - Pandanus Associates, Inc.
Item 2: 	   	(a)  	[ ]
   	   	(b)  	[ ]
Item 4: 	   	Delaware
Item 5: 	   	0
Item 6: 	   	0
Item 7: 	   	28,954,248
Item 8: 	   	0
Item 9: 	   	28,954,248
Item 11: 	   	8.386%
Item 12: 	   	CO
 
Item 1(a). 	    	Name of Issuer:
 
  	  	          	21VIANET GROUP INC
 
Item 1(b). 	    	Address of Issuer's Principal Executive Offices:
 
  	  	          	M5, 1 Jiuxianqiao East Rd
Chaoyang District
  	  	          	Beijing, F4 100016
  	  	          	China
 
Item 2(a). 	     	 Name of Person Filing:
 
  	   	               	 FIL Limited
 
Item 2(b). 	     	 Address or Principal Business Office or, if None, 
Residence:
 
  	   	               	 Pembroke Hall, 42 Crow Lane, Hamilton, Bermuda, 
HM19
 
Item 2(c). 	     	 Citizenship:
 
  	   	               	 Not applicable
 
Item 2(d). 	     	 Title of Class of Securities:
 
  	   	               	 CLASS A COMMON STOCK
 
Item 2(e). 	     	 CUSIP Number:
 
  	   	               	 90138A921
 
Item 3. 	    	This statement is filed pursuant to Rule 13d-1(b) or 13d-2(b) 
or (c) and the
person filing, FIL Limited, is a non-U.S. institution in accordance with
Section 240.13d-1(b)(1)(ii)(J).   (Note:  See Exhibit A).
  	    	  
  	    	  
  	    	If filing as a non-U.S. institution in accordance with Section 
240.13d-1(b)(1)(ii)(J),
please specify type of institution: Parent holding or control person.
 
Item 4. 	    	Ownership
 
  	  	     	(a)    Amount Beneficially Owned: 	28,954,248
 
  	  	     	(b)    Percent of Class: 	8.386%
 
  	  	     	(c)    Number of shares as to which such person has:
 
  	  	     	       (i)    sole power to vote or to direct the vote: 	
15,812,820
 
  	  	     	       (ii)    shared power to vote or to direct the vote: 	0
 
  	  	     	       (iii)    sole power to dispose or to direct the 
disposition of: 	28,954,248
 
  	  	     	       (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.
 
  	    	     	Not applicable.
 
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.
 
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 and are held in the ordinary 
course of business and were not acquired and are not held for the purpose 
of or with the effect of changing or influencing the control of the issuer 
of the securities and were not acquired and are not held in connection with 
or as a participant in any transaction having that purpose or effect. By 
signing below I certify that, to the best of my knowledge and belief, the 
foreign regulatory scheme applicable to FIL Limited and its various 
non-U.S. investment management subsidiaries included on this Schedule 13G 
is 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.

 
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.

  	February 13, 2015
  	Date
 
  	/s/ Scott C. Goebel
  	Signature
 
  	Scott C. Goebel
  	 Duly authorized under Power of Attorney effective as of May 5, 2014, by 
and on behalf of FIL Limited and its direct and indirect subsidiaries*
 
 

        * This power of attorney is incorporated herein by reference to 
Exhibit B to the Schedule 13G filed by FIL Limited on June 10, 2014, 
accession number: 0000318989-14-000096.

 

Exhibit A
 

                 Pursuant to the instructions in Item 7 of Schedule 13G, 
the following table lists the identity and Item 3 classification, if 
applicable, of each relevant entity that beneficially owns shares of the 
security class being reported on this Schedule 13G.

 
Entity 	ITEM 3 Classification
FIL INVESTMENT MANAGEMENT (HONG KONG) LIMITED 	FI
FIL INVESTMENT MANAGEMENT (SINGAPORE) LIMITED 	FI
FIL INVESTMENTS INTERNATIONAL 	FI
FIL LIMITED 	FI
FIL PENSION MANAGEMENT 	FI
  	 
  	 

                Pandanus Partners, L.P. ("Pandanus") owns shares of FIL 
Limited ("FIL") voting stock. While the percentage of total voting power 
represented by these shares of FIL voting stock 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. 
Pandanus Associates, Inc. ("PAI") acts as general partner of Pandanus. 
Pandanus is owned by trusts for the benefit of members of the family of 
Edward C. Johnson 3d but disclaims that any such member is a beneficial 
owner of the securities reported on this Schedule 13G.

 

                This filing reflects the securities beneficially owned, or 
that may be deemed to be beneficially owned, by FIL, certain of its 
subsidiaries and affiliates, and other companies (collectively, the "FIL 
Reporters"). This filing does not reflect securities, if any, beneficially 
owned by certain other companies whose beneficial ownership of securities 
is disaggregated from that of the FIL Reporters in accordance with 
Securities and Exchange Commission Release No. 34-39538 (January 12, 1998).

 
RULE 13d-1(k)(1) AGREEMENT
 

                The undersigned persons, on February 13, 2015, agree and 
consent to the joint filing on their behalf of this Schedule 13G in 
connection with their beneficial ownership of the CLASS A COMMON STOCK of 
21VIANET GROUP INC at December 31, 2014.

 
  	FIL Limited
 
  	By /s/ Scott C. Goebel
  	Scott C. Goebel
  	Duly authorized under Power of Attorney effective as of May 5, 2014, by 
and on behalf of FIL Limited and its direct and indirect subsidiaries*
 
  	Pandanus Partners, L.P.
 
  	By /s/ Scott C. Goebel
  	Scott C. Goebel
  	Duly authorized under Power of Attorney effective as of May 2, 2014, by 
Pandanus Associates, Inc. on behalf of Pandanus Partners, L.P.*
 
  	Pandanus Associates, Inc.
 
  	By /s/ Scott C. Goebel
  	Scott C. Goebel
  	Duly authorized under Power of Attorney effective as of May 2, 2014, by 
and on behalf of Pandanus Associates, Inc.*
 
 

        * This power of attorney is incorporated herein by reference to 
Exhibit B to the Schedule 13G filed by FIL Limited on June 10, 2014, 
accession number: 0000318989-14-000096.