The present invention relates to a wireless communication system, more specifically a method for transmitting uplink through random access, and comprises: a step for receiving from a base station a first message which includes Machine Type Communication (MTC)-specific bandwidth request channel information for requesting bandwidth of MTC terminals; and a step for transmitting to the base station through the MTC-specific bandwidth request channel at least on of either bandwidth request preamble and bandwidth request information, wherein the bandwidth request information includes at least one of the following: MTC terminal identifier, quality of service (QoS), bandwidth request indicator, and bandwidth request size.