PURPOSE: To prevent damage to the edge of positioning holes by positioning pins.

CONSTITUTION: A workpiece 1, such as a lead frame, having a positioning hole 12, is placed on a table 2 and plunged UP by a positioning pin 5 from below. A guide hole 4 is formed in the table 2 to guide the positioning pin 5, which is composed of the rod of a cylinder 10. An ultrasonic vibrator 14 is secured on the cylinder 10, and vibrates the positioning pin 5 by ultrasonic waves through ON operations (13). Being vibrated by ultrasonic waves, the positioning pin 5 is inserted into the positioning hole 12 in the workpiece positioned on the table 2. The edge of the positioning hole 12 is supported by the tapered portion 6 of the positioning pin 5 and is being vibrated by ultrasonic waves. Therefore, the edge of the positioning hole 12 drops along the slope, and the workpiece is properly positioned even if the positioning hole 12 is initially out of place. This does not exert large force on the edge of the positioning hole 12, and thus does not deform (damage) it.