Optical part assembly

An optical part assembly comprising:

• a mirror main body including a base and a mirror support section that is formed integral with the base and having a projected tip;
• a mirror mounted on the projected tip of the mirror support section;
• a casing that accommodates the mirror main body, the casing having at its tip part an opening in which the mirror support section is exposed, and the casing having a rear end part closed with a bottom plate;
• a plurality of driving sections that are disposed on the bottom plate of the casing and act on the base to swing the base;
• a ring member that has an opening and is fixed to a front end part of the casing;
• and
• a bellows seal of which one end makes contact with a front end of the base, and the other end makes contact with the ring member to surround the mirror support section.