The present invention relates to a wireless communication system and particularly to a method and a device for the method, the method comprising: a step of receiving a subframe having a control duration configured with a plurality of OFDM symbols; a step of receiving a control channel by monitoring a plurality of control channel candidates in the control duration of the subframe; and a step of performing an operation corresponding to the control channel, wherein, if the plurality of OFDM symbols correspond to multi-beam directions, a plurality of control channel resources constituting each control channel candidate are present only in the same OFDM symbol in the control duration, and if the plurality of OFDM symbols correspond to a single-beam direction, the plurality of control channel resources constituting each control channel candidate are present across the plurality of OFDM symbols in the control duration.