To propose an optical system for a portable individual authenticating device which can photograph iris information for individual authentication and is small, inexpensive and suitable to be incorporated in a portable communication device.

This optical system 21 for portable individual authentication has an optical system 26 for full image photographing provided with an object lens 22, a first solid-state image pickup device 23 and a first lens 25 for converging incident light L24 through the object lens 23 on the first solid-state image pickup device 23, and an optical system 32 for iris photographing provided with a light source 28 for partial illumination for illuminating a portion of an area within a photographing area by the optical system 26 for full image photographing, the object lens 22, a second solid-state image pickup device 29 and a second lens 31 for converging incident light L30 made incident from an irradiation area by the light source 28 for partial illumination through the object lens 22 on the second solid-state image pickup device 29. Iris information for individual authentication can be acquired from the solid-state image pickup device 29 of the optical system 32 for iris photographing.