A method for controlling a robot cleaner includes: detecting a cleaning target space, setting a cleaning region within the detected cleaning space and cleaning the set cleaning region; if the set cleaning region is completely cleaned, moving to a not-yet-cleaned region adjacent to a cleaning completion spot of the cleaning region; and setting a new cleaning region in the not-yet-cleaned region and performing cleaning. Without repeating a cleaning region in the cleaning target space, the robot cleaner can extend its cleaning region, so the cleaning efficiency of the robot cleaner can be improved. Also, the robot cleaner can be smoothly enter a new cleaning target space or released therefrom. In particular, even when the entrance of the new cleaning target space is narrow, the robot cleaner can smoothly enter the new cleaning target space and gets out thereof.