A cleaning robot to prevent a suction member from moving upwards when the suction member is rotated during a collision with an obstacle, and which completely unfolds the suction member when a lower surface of the suction member travels on an uneven floor. The cleaning robot includes a main body to travel on a floor to be cleaned, a dust collecting unit, and a corner cleaning unit. The corner cleaning unit includes a suction member having a suction arm with a rotatable cylinder, a movable member rotatably coupled around the rotatable cylinder by a torsion spring such that the movable member can move upwards and downwards together with the suction member, a driving unit, supporting brackets, at least one elevation guide face to allow the movable member to move upwards and downwards along the elevation guide face as the movable member rotates, and at least one guide knob.