Wafers are previously positioned so that the wafer orientation flat is oriented in a particular direction. A transporting means then moves and places the previously positioned wafer on a bonding stage where bumps are formed on the wafer by means of a bonding head. The transporting means has a sensor for detecting the position of the orientation flat of a wafer on the bonding stage from a position above the bonding stage, thereby avoiding the adverse effects of heat from the bonding stage during orientation flat detection.