To provide a light shielding plate, which is superior in characteristics to drive reflected light in each part of an optical system to the outside of the optical axis and which has improved flare, and to provide a lens system having this plate.

This light shielding plate 5 is annular to have a center part, where an aperture spread around an optical axis is formed, and intercepts light in the peripheral area on the outside of the optical axis; and the aperture peripheral edge of the light shielding plate consists of a front plate 11 inclined so as to project to the object side and of a rear plate 13 inclined so as to project to the image side. Since the light shielding surface is not right-angled but inclined to the optical axis, the light shielding plate is superior in characteristics to drive unnecessary reflected light to the outside of the optical axis and can reduce flare of an image.