a joining roller rolls on the surface of a reinforcing substrate held by a center and side latch claws so as to be close and opposite to an wafer placed and held on a holding table in the condition that an adhesive sheet is adhered on the surface , whereby joining proceeds . as the joining roller rolls , both of the latch claws oscillate downward and the latch claws themselves move down while keeping the bend of the reinforcing substrate nearly constant , and retract when the joining roller approaches the latch claws .