Provided are a method for transmitting a buffer status report (BSR), and a device thereof, and to: a method by which a first terminal transmits and receives a BSR required for performing device-to-device communication with a second terminal in order to efficiently allocate a wireless resource to be used for the device-to-device communication; and a device therefor. Specifically, provided are a method and a device by which the first terminal performs device-to-device communication with the second terminal. Such a method includes triggering a BSR for the device-to-device communication with the second terminal, transmitting the BSR to a base station or a wireless resource allocation entity, and receiving wireless resource allocation information for the device-to-device communication with the second terminal from the base station or the wireless resource allocation entity.