PURPOSE: To make it possible to conduct accurately a wiring bonding work even if the positioning of a stem using a support jig is rough and to make it possible to heat the stem in a short time and efficiently even when the stem is heated.

CONSTITUTION: A stem 6 is transferred in such a way that it is housed in a stem housing part of a tray 7 and is transferred from this transfer path to a positioning means 9. On the means 9, the stem 6 is heated by a heater and at the same time, the positions of electrodes 3a and 3b of a semiconductor pellet 3 on the stem and the positions of leads 6a and 6b of the stem are respectively recognized by a recognition means, a capillary 13 is moved while being controlled on the basis of the recognition result and leads 6a and 6b are wire bonded to the electrodes 3a and 3b.