PURPOSE: To provide a compound lens by which the pattern of a diffraction grating can be accurately transferred, whose inside refractive index does not become uneven because of environmental change, which has stable lens performance and where chromatic aberration is corrected.

CONSTITUTION: A glass lens 1 which is hardly influenced by the environmental change is used as a lens having refracting action, and a diffraction element 2 is bonded with the glass lens, so that the compound lens is constituted. The surface of the element 2 on a side which is not bonded with the glass lens 1 is formed to be like stairs so that lens thickness may be large as plural zonal surfaces which are concentric circles with respect to an optical axis separate from the optical axis.