In this optical device, a base and a movable part are formed from a semiconductor substrate having, provided in order from one side in a prescribed direction, a first semiconductor layer, an insulating layer, and a second semiconductor layer. The base is formed from the first semiconductor layer, the insulating layer, and the second semiconductor layer. The moveable part is provided with a placement part formed from the second semiconductor layer. An optical functional part is placed on the surface of the placement part at the one side. The first semiconductor layer which forms the base is thicker than the second semiconductor layer which forms the base. The surface of the base at the one side is positioned further towards the one side than the optical functional part.