To excellently compensate aberration by providing a 2nd diffraction surface arranged nearer to an image surface side than a 1st diffraction surface and having negative refractive power and constituting the respective diffraction surfaces of a diffraction grating having rotationally symmetric shape with respect to an optical axis.

At least one plate-like optical member L3 equipped with the 1st diffraction surface A arranged nearer to the image surface side than a 2nd lens group L2 and having positive refractive power, at least one plate-like optical member L4 equipped with the 2nd diffraction surface B arranged nearer to the image surface side than the surface A and having the negative refractive power, and an optical member L5 such as a filter are arranged in this system. The surfaces A and B are constituted of the diffraction grating having the rotationally symmetric shape with respect to the optical axis. In the case of arranging the diffraction grating at the rear of an optical system capable of making the diameter of an element comparatively small, the aberration coefficiency of the axial chromatic aberration and the transverse chromatic aberration of an entire system is made small simultaneously by preparing two diffraction surfaces having the positive refractive power and the negative refractive power and arranging them at appropriate positions.