To increase a number of aperture diameters provided on an aperture member without sacrificing compactness of a camera and the like.

A camera with an aperture mechanism includes: a camera body 10; a lens barrel LU which protrudes from the camera body; and an aperture mechanism. The aperture mechanism includes; a disk-like aperture member 50 which has a plurality of aperture openings, is rotatable about a rotation axis parallel to an optical axis, and moves integrally with the lens barrel along an optical axis direction; a manual manipulation ring 20 which is mounted in a manner which allows rotation thereof about the optical axis with respect to the camera body; an interlocking mechanism (27, 51, 60) which transforms rotational motion of the manual manipulation ring to rotational motion of the aperture member to have the manual manipulation ring interlocked with the aperture member; a click mechanism (70, 71) capable of holding the aperture member at an aperture position for each of the plurality of aperture openings; and a return spring 30 which automatically turns the manual manipulation ring back to an initial position corresponding to a predetermined aperture value when the click mechanism releases the hold on the aperture member. This allows for increasing the number of aperture openings of different diameters on the aperture member as well as achieving compactness of the lens barrel and the like.