An optical device includes: an optical element having an optically functional surface which is pivotable; a base supporting the optical element; and a package housing the optical element and the base, in which the package includes: a wall that surrounds the optical element and the base; a window that closes a first opening defined by the wall, and forms an optical path to the optically functional surface, the window being transmissive to light; and a bottom plate that closes a second opening defined by the wall.