Proposed is an operation method of a first device (100) in a wireless communication system. The method may comprise the steps of: establishing a sidelink (SL) unicast link with a second device (200); transmitting first SL discontinuous reception (DRX) configuration information related to the SL unicast link to the second device (200); transmitting a physical sidelink control channel (PSCCH) to the second device (200) in an on-duration interval included in the first SL DRX configuration information; and transmitting a physical sidelink shared channel (PSSCH) to the second device (200) on the basis of the PSCCH in the on-duration interval.