A robot cleaner including: a main body, a driving unit configured to move the main body, and a suction device provided in the main body and configured to suction outside foreign substances, and the suction device may include a first suction member having a suction port provided at a bottom surface of the main body and configured to suction the foreign substances, and at least one second suction member formed to move relative to the first suction member and having a suction port configured to suction the foreign substances.