a cleaning apparatus capable of sufficiently removing foreign matters such as coating or labels from surfaces of crushed pieces of the collected polymeric mold product is provided . the cleaning apparatus includes a cleaning bath provided with a rotary shaft extending in the longitudinal direction and having a water supply port , a drainage port as well as an introduction port and a discharging port for polymeric pieces , screw sections having a screw provided on the rotary shaft and flow - path restricting sections having stationary plates standing upright from the inner surface of the cleaning bath to restricting the advancement of water caused by the screw , wherein at least part of a surface of the stationary plate is roughened .