The method for a user equipment (UE) transmitting a buffer status report (BSR) comprises receiving logical channel configuration information from a network, the logical channel configuration information including information related to a plurality of numerologies mapped to each logical channel; when the BSR is triggered, selecting a buffer size reporting numerology for each logical channel; calculating a buffer size for a numerology by including a buffer size of logical channels having the buffer size reporting numerology as the numerology; and reporting the BSR including information of the calculated buffer size.