The present invention relates to a method for transmitting a downlink control channel in a wireless communication system, and an apparatus therefor. Specifically, the method for transmitting an enhanced a physical downlink control channel (EPDCCH) from a serving cell comprises the steps of: forming a plurality of enhanced resource element groups (EREGs) by dividing available resource elements, comprised in one physical resource block (PRB) pair, into a predetermined number; forming an enhanced control channel element (ECCE), which is a resource allocation unit for the EPDCCH, by selecting one or more EREGs from among the plurality of EREGs; and transmitting the EPDCCH by means of the transmission resource allocated, for each ECCE, for the EPDCCH, wherein one or more EREGs forming the ECCE is selected on the basis of a cell identifier of the serving cell and/or an index of the one PRB pair.