PURPOSE: To aim at the facilitation of a change in an implanting angle by tilting a holding surface, holding a semiconductor device, and a bottom surface in contact with a main holder both at the specified angle, when a subholder is attached to the main holder and the semiconductor device is supported.

CONSTITUTION: A holder 19 is installed at the most downstream side of an ion beam 15, and it has a main holder 17 to be rotated by a turning shaft 20 and plural numbers of subholders 18 radially attached to the front of the main holder 17. The main holder 17 has a supporting surface 17a titled as far as an angle θ1 to the central surface 17b at the outer circumferential side of the front. The front of the subholder 18 to be attached to this supporting surface 27a comes to a holding surface 18a holing a semiconductor wafer 16. In addition, the subholder 18 is rotatably attached to the main holder 17 by a pin shaft 18b around it. The holding surface 18a of the subholder 18 is tilted as far as an angle θ2 to the bottom 18c. In this constitution, a changeover of an incident angle θ3 of the ion beam 15 into the semiconductor wafer 16 is made possible.