An aperture apparatus includes a substrate having a lens opening, a first aperture sector having a first aperture opening, a second aperture sector having a second aperture opening, and a drive pin that is engaged in cam openings respectively formed in the first aperture sector and in the second aperture sector and that swings the first aperture sector and the second aperture sector. The first aperture sector and the second aperture sector are located in receding positions from the lens opening, when the drive pin is in an initial position. The cam openings include a swing region and a non-swing region, the swing region guiding a corresponding sector to the lens opening as the drive pin moves from the initial position, the non-swing region retaining the other sector in the receding position, when one of the first aperture sector and the second aperture sector is guided to the lens opening.