PURPOSE: To enable the formation of a distortion detecting section onto a fine three-dimensional surface by directly evaporating and drawing a resistance pattern on the surface of a mechanical structure by using a focused ion beam device.

CONSTITUTION: A metal having a large gauge coefficient such as Ni, Cr or the like is used as a liquid metallic source for a focused ion beam device, a catheter as a target is placed on a stage 15, and the surface of the distortion detecting section 1a of the catheter 1 is irradiated with focused ion beams at low speed and a resistance material such as Ni is evaporated directly. A resistance pattern 2 is evaporated and drawn directly on the surface of the distortion detecting section 1a of the catheter 1 by moving and rotating the catheter 1 by shifting the stage 15 at that time. The resistance pattern 2 is formed, sections except a bonding pad 2a are covered with an insulating film 3, and a signal conductor 4 is connected. Accordingly, since the resistance pattern having little impurities can be formed, stable detection characteristics having a small change with time in detectivity can be obtained.