PURPOSE: To properly maintain the inner diameter of a pressed-in part having a through-hole with high accuracy after a pressing-in process by providing an A-shaft for actuating a tilt motion under numerical control, and a B-shaft for actuating a tilt motion right and left under numerical control.

CONSTITUTION: A servo motor 12 tilts a substrate 15 back and forth using an A-shaft member 14 connecting an elevator plate 13 to the substrate 15 as a support point, so that the axial direction of a through-hole in a workpiece W is kept in parallel to a vertically mounted rod type jig at the forward end of a hydraulic cylinder and a vertical tubular jig where the end of the rod type jig penetrates. Furthermore, another servo motor 16 tilts right and left a fastener 18 for holding a workpiece W using a B-shaft member connecting the substrate 15 to the fastener 18 as a support point. Also, another servo motor drives and controls a Y-shaft member 2 and an X-shaft member 6, and the axial center of the vertically positioned through-hole is maintained at a pressing-in position immediately above the rod type jig. According to this construction, a well satisfactory result can be provided, even when an allowable tolerance is stringently set.