A light intensity control device includes a fixed opening 261, an aperture stop part 26 for controlling a light flux of incident light, a light intensity aperture part 24 for changing the size of an opening by moving a plurality of aperture blades to limit a light intensity of transmitted light and a ND filter 25 having a transparent area 253 and a light blocking area 254, which is arranged to be movable between a first light blocking state where the transparent area 253 faces the fixed opening 261 of the aperture stop part 26 and a second light blocking state where the light blocking area 254 faces the fixed opening. The moving of the ND filter 25 is carried out when the opening area of the light intensity aperture part 24 is a maximum.