A method of receiving a control signal by a user equipment in a wireless communication system is disclosed. The present invention includes receiving control regions including the control channel relevant to each of a plurality of component carriers via a plurality of component carriers and detecting the control channel for the user equipment by performing blind decoding by a unit of CCE (control channel element) aggregated at a preset level in a search space included in the control regions. And, start positions of the search spaces in the plurality of component carriers is in a certain relationship. Moreover, the preset level is identically set for each of the plurality of component carriers.