According to one embodiment, a focus position changing apparatus is provided on an optical path of a confocal optical apparatus having a light source and an objective lens and is configured to change a focus position of the objective lens in an optical axis direction of the objective lens. The focus position changing apparatus includes at least a plurality of optical path changing pieces and a rotating plate. Each of the plurality of optical path changing pieces is differ from each other in at least one of a refractive index and a thickness. On the rotating plate, the plurality of optical path changing pieces is arranged along a rotation direction of the rotating plate so as to cross an optical axis of the objective lens. And an anti-reflection layer is formed in a predetermined region on a surface of the rotating plate on a side of the light source.