Disclosed is a method for a terminal to report channel state information (CSI) in an unlicensed band. In particular, this disclosure includes: receiving a channel state information-reference signal (CSI-RS) through at least one listen before talk (LBT) sub-band among a plurality of LBT sub-bands; measuring a plurality of pieces of CSI for each of the plurality of LBT sub-bands; generating wideband CSI for all of the plurality of LBT sub-bands on the basis of the plurality of pieces of CSI; and reporting the generated wideband CSI to a base station.