PURPOSE: To provide an optical lens which can correct imaging system characteristics such as field curvature and spherical aberration.

CONSTITUTION: This optical lens is constituted of a simple optical element, and additional magnification is not introduced to an optical system. This correcting lens is a(plane recessed or plane projecting) element based on a plane, and it is provided with a series of stepped areas 14 formed in parallel 16/vertically 18 to the plane surface. The stepped profile of this correcting lens is decided so that curvature R of the lens for applying curvature for substantially offsetting prescribed aberration peculiar to a picture system to a wave surface passing through this lens can be approximated. This correcting lens can be used for correcting the field curvature, spherical aberration, and both. This correcting lens is formed so as to be made permeable or reflective according to a request from the system.