A method for monitoring a control channel in a wireless communication system is provided. The method includes: dividing a control region of a subframe into a common search space having a variable size and monitored by every user equipment (UE) within a cell and a dedicated search space having a variable size and including at least one UE-specific search space to be monitored by at least one UE within the cell, and monitoring a control channel within the common search space; and monitoring a control channel within the UE-specific search space included in the dedicated search space. The performance of an overall system can be improved by effectively monitoring a downlink control channel.