PURPOSE: To eliminate the need for the provision of an additional alignment process and to improve the efficiency by forming a notch used as a mark in each manufacture process simultaneously in the process of punching out a reflecting mirror.

CONSTITUTION: A rib 10 is formed to the circumferential ridge of a reflecting mirror 3 in the process punching out the reflecting mirror 3 and at least two notches 10a, 10b are formed to the rib 10 at its opposite position as soon as the reflecting mirror 3 is punched out. A reflecting mirror mount metallic fixture 4 is bonded to the reflecting mirror 3 while using the notches 10a, 10b as the reference of the alignment in the next process and an electronic device case mount metallic fixture 5 is bonded similarly in the next process by using the notches 10a, 10b as the reference. Thus, the reflecting mirror mount metallic fixture 4 and the electronic device case mount metallic fixture 5 are fitted to the position of the reflecting mirror as designed. Then the designed characteristic is obtained without additional provision of the alignment process and then the job efficiency is improved.