PURPOSE: To perfectly take out dirt by one washing operation due to high capacity of a washing device when a floor surface of concrete is washed, and can suck up dust, wastewater, and the like.

CONSTITUTION: This washing device for concrete floor is constituted of a rotary disc 3 rotating by a motor 2, three rotary brushes 4 provided on the bottom face of the rotary disc 3, a base body 5 loading the motor 2 and holding the rotary disc 3, and a push handle 6 fitted to the base body. When the motor 2 is driven, all the respective rotary brushes 4 are rotated in the same direction in addition to rotation of the rotary disc 3, dust, wastewater, and the like are gathered in the vicinity of the nearly center of the bottom face of the rotary disc 3, and the dust and the like are sucked up through a suction port.