1. A method for performing serving gateway (S-GW) relocation in a wireless communication system, the method performed by a mobility management entity (MME) and comprising:receiving location information of a serving small cell, which is served by a second evolved NodeB (eNB), from a first eNB which supports dual connectivity to a specific user equipment (UE) with the second eNB, wherein each of the first eNB and the second eNB is connected to a first S-GW;
transmitting the received location information of the serving small cell to a second S-GW, when the MME determines that the first S-GW of the second eNB should be changed to the second S-GW for an overload; and
performing the S-GW relocation based on the determination,
wherein after the S-GW relocation, the first S-GW is connected to the first eNB and the second S-GW is connected to the second eNB while a dual connectivity state between the first eNB and the second eNB is maintained.