The present invention relates to a wireless communication system. More specifically, the present invention relates to a method and a device for canceling scheduling requests triggered by a sidelink buffer status report in a D2D communication system, the method comprising: receiving an uplink grant while one or more Scheduling Requests (SRs) are pending, wherein all of the one or more SRs are triggered by sidelink Buffer Status Report (BSR); generating a MAC (Medium Access Control) PDU (Protocol Data Unit); and canceling the all of the one or more pending SRs if the MAC PDU includes a sidelink BSR MAC CE (Medium Access Control Control Element).