PURPOSE: To efficiently fix two parts without hurting the external appearance, by thrusting the flat roller built in the notch of the shank against one of set and rotating two parts.

CONSTITUTION: At first, the parts 1, 2, are set, in case of fixing, etc., of the external parts of the watch. The chunnel shape notch 7 is formed in a part of the shank 6, and the freely rotatable flat roller 8 is built in the notch 7. This jig is set to the plane stock, etc., of the lathe, and the flat roller 8 is thrusted against the end face of the part 1 while the part 1 and the part 2 are being rotated. Hereby, the material of the part 1 causes the plastic deformation inward and caulks the part 2. According to this method, the caulking limit for two parts is improved, and the design elements for the exterior parts can be widened.