Provided is a light amount control device eliminating a deviation in image forming position over the entire area of the variable range of an aperture due to an ND filter and assuring smooth stopping operation. The light amount control device of the present invention includes: a first shading member and a second shading member which are adapted to move within a plane perpendicular to an optical axis to vary an area of a light passage opening; a lever member which is connected with the first shading member and the second shading member and which is rotatable; an actuator for driving the lever member; and an ND filter mounted to the first shading member. The ND filter is configured to cover an entirety of the light passage opening in an open state, and the second shading member has a guard portion which, with the light passage opening being in a closed state, is arranged between the lever member and the ND filter, preventing the ND filter from coming into contact with the lever member.