The present invention is a processing apparatus comprising a transfer mechanism including at least one transfer plate, the transfer mechanism being configured to cause, when a substrate to be processed is placed on an upper surface of the transfer plate, the transfer plate to move while maintaining the substrate to be processed placed horizontally thereon. The transfer plate has a cantilevered support structure horizontally extending from a proximal end thereof to a distal end thereof in a fore and aft direction. An upper surface of the transfer plate is provided with a plurality of support projections configured to horizontally support the substrate to be processed at a substantially central position thereof and a rear position thereof in the fore and aft direction. The substrate to be processed is not supported on the distal portion of the transfer plate.