To provide a device for changing image plane illuminance which provides light quantity correction effect in accordance with focal length by using a single light quantity ratio change optical element.

In the device for changing image plane illuminance, a light quantity change member the transmissivity of which changes in a direction perpendicular to an optical axis O is arranged in the middle of an optical path of a zoom lens to reduce illuminance difference of the image plane. One of the lenses constituting another 3rd lens group 13 having a changing space to a diaphragm 21 which is provided in the middle of the optical path of the zoom lens and which moves along the optical axis in accordance with zooming is made to be a transmissivity change lens 132 being the light quantity ratio changing member.