The present description provides a method for allocating a device identifier through an initial network entry process with a base station in a wireless access system. The method comprises a step of transmitting control information, indicating a mobile station supporting Machine to Machine (M2M) communication, to a base station; and receiving a first message, comprising at least one of a first identifier indicative of a group to which devices belong and a second identifier indicative of each of the devices belonging to the group, from the base station.