According to an embodiment of the present disclosure, provided is a method by which a first apparatus performs sidelink communication. The method may comprise the steps of: transmitting a first transport block to a second apparatus, on a resource allocated by a first SL grant received from a base station; transmitting, to the base station, a system information request message requesting system information; transmitting, on an exceptional resource pool, a second transport block to the second apparatus, on the basis of the transmission of the system information request message to the base station; and receiving, from the base station, first system information related to the system information request message.