PURPOSE: To provide the waste material crushing method which is relatively few in problems with environmental measures relating to the noise, dust, etc., generated in the case of operation by installing a waste material crushing machine or sorting machine to a specific place and is low in a cost for crush treatment and the device therefor.

CONSTITUTION: The crushing machine 20 or sorting machine is installed on a transporting base plate 30 with outrigger jacks 33. This transporting base plate 30 is placed on a trailer and is transported near to an operation site. The transporting base plate 30 is then lifted by the outrigger jacks 33 and the trailer is removed; thereafter, a moving truck 40 is inserted to join the moving truck 40 and the transporting base plate 30, which are then moved to the prescribed working place and are used for carrying out the operation.