The present invention relates to a wireless communication system and, specifically, provides a method for reporting a channel state and an apparatus therefor. A terminal of the present invention receives, from a base station, configuration information for a plurality of sets, each including at least one of a plurality of channel state information-reference signal (CSI-RS) resources configured for a channel state information (CSI) process. The terminal reports CSI measured on the basis of only at least one CSI-RS resource included in a first set which is one of the plurality of sets. Here, the first set may include only some CSI-RS resources of the plurality of CSI-RS resources configured for the CSI process.