PURPOSE: To ensure that the management and maintenance of a finished product can be achieved without giving any adverse effect to production by making a finished product recovery box attached to an injection molding machine detachable for replacement without stopping the operation of the machine.

CONSTITUTION: An operating valve 8 which opens in the direction of a transport tube 101 is installed in a freely rocking manner at the feed-out orifice 7 of a main valve system 4 provided halfway through the transport tubes 31, 101 leading from an injection molding machine to a product recovery box. At the same time, an exhaust orifice 11 for exhausting air from the nozzle part of the injection molding machine to the main valve system is provided on the lateral wall of the main valve system, and an aspiration orifice 12 for sending a compressed air into the main valve system 4 instantaneously is provided on the other lateral wall. Thus a finished product is sent into the transport tube 101 by pressing the operating valve 8 open.