PURPOSE: To enable image formation on a prescribed image plane in the state in which aberration are well corrected at all times by selecting the radii of curvature, thicknesses, refractive indices, dispositions, etc., of respective lenses in a manner as to satisfy respective conditions.

CONSTITUTION: The projection lens is so constituted as to satisfy the conditions expressed by equation I W equation VII where the radii of curvature of the respective faces of said lens are designated, successively from the image plane side when the lens is to be used at a macromagnification, as R1, R2, R3, R4, R5, R6, the inter-face spacings between the respective faces of this projection lens are designated, successively from the image plane side when the lens is to be used at the macromagnification, as D1, D2, D3, D4, D5, the focal length of the entire system when the inter-face spacing D2 is maximized is designated as fw, and the focal lengths and refractive indices of the respective lenses of the projection lens are designated, successively from the image plane side when the lens is to be used at the macromagnification, as f1, f2, f3, and N1, N2, N3. The fluctuations in the aberrations at the time of lens movement are thereby decreased and the always good projection state is maintained.