To efficiently crush a lumpy object, for example, a lightweight aerated concrete(ALC) panel, especially, an uncured semiplastic lumpy object (semiplastic object) and to certainly remove even crushed refuse bonded to a base plate.

A lumpy object crushing apparatus is equipped with a movable base plate 4 on which a lumpy object W to be crushed is placed and a rotatable crushing drum 3 successively crushing the lumpy object W placed on the base plate and the crushing drum 3 is constituted of a rotary center shaft 31, a plurality of flat plates 32 and spiral plates 33a, 33b provided on the periphery of the rotary center shaft and a plurality of the horizontal rods 34 provided to the outer peripheries of the flat plates and the spiral plates and extending over the total length of the drum in the bus direction thereof. A scraper 5 for scaping off the crushed refuse remaining on the base plate is provided behind the crushing drum 3 and brought into contact with the base plate by a pressure means 6 such as a hydraulic cylinder under predetermined pressure.