Patent ID: 7744295

Claim:
An aperture mechanism comprising: a first member to rotate in accordance with aperture operation; a rotation regulating section having a first inclined surface inclined with respect to a rotational axis of the first member to regulate rotation of the first member; and a second member having a second inclined surface that is inclined with respect to the rotational axis and transfers a rotational driving force between the second inclined surface and the first member, and a third inclined surface provided on a side opposite to the second inclined surface, to rotate in accordance with aperture operation; wherein the first member has a projection section opposed to the third inclined surface; and the inclination of the third inclined surface with respect to a line parallel with the rotational axis is smaller than the inclination of the second inclined surface, and when the first member and the second member move relatively along the rotational axis in a direction in which an aperture becomes small, a clearance occurs between the third inclined surface and the projection section.