The present invention relates to a method of transmitting a downlink control channel including one or more control channel elements to a terminal by a base station in a wireless communication system. In particular, the method includes: allocating an antenna port of a demodulation-reference signal (DM-RS) to the one or more control channel elements that configure the downlink control channel; and transmitting the downlink control channel to the terminal by using the DM-RS of the allocated antenna port, wherein the antenna port of the DM-RS is determined on the basis of the number of control channel elements per resource block.