Provided are a method for allocating a temporary radio network temporary identifier to a terminal within a random access procedure in a wireless communication system, and an apparatus supporting the same. The method for allocating a temporary radio network temporary identifier (T-RNTI) to a user equipment (UE) within a random access procedure in a wireless communication system, includes transmitting, by the UE, a random access preamble to a base station (BS), transmitting, by the UE, a radio resource control (RRC) request message to the BS through a contention-based physical uplink shared channel (PUSCH) resource block in which uplink data can be transmitted without uplink resource allocation scheduling, and receiving, by the UE, an RRC connection setup message identified by a T-RNTI allocated to the UE in response to the RRC request message, wherein the T-RNTI is allocated on the basis of the contention-based PUSCH resource block in which the RRC request message has been transmitted.