A temporary receiving unit of a processing apparatus includes a first support rail having a first bottom wall and a first side wall for guiding a workpiece for sliding movement in unloading and loading directions of the workpiece by an unloading and loading unit, a second support rail disposed in an opposing relationship to the first support rail and having a second bottom wall and a second side wall for guiding a workpiece for sliding movement, a support rail actuation unit for actuating the first support rail and the second support rail in directions in which the first support rail and the second support rail approach each other and are spaced away from each other, and a load detection unit for detecting a load on the support rail actuation unit.