PURPOSE: To provide the excellent quality of picture whose aberrations including distortion aberration and the curvature of field are compensated while ensuring a working space for wiping out dust stuck to a monitor due to static electricity and a space for arranging a rotating filter in an optical path by composing the device of four lens groups of negative, positive, negative and positive lenses.

CONSTITUTION: This device is composed, in order from the object side, of a first lens group composed of a negative meniscus lens whose convex surface confronts the object side, a second lens group composed of a positive lens whose curvature of a surface on the object side is larger than the curvature of a surface on the image side, a third lens group composed of biconcave lens, a fourth lens group whose curvature of a surface on the object side is smaller than the curvature of a surface on the image side and a brightness diaphragm arranged between the second lens group and the third lens group. When the device is utilized for the image photographic device of a monitoring television, by representing a distance from a display means to a projection optical system by L, the distance L satisfies the condition: (1) 1.5f<L<3f, where (f) is the focal distance of the whole optical system.