To enhance the gradation reproducibility and to reduce the photographing time by introducing an object light passing through a lens to respective light receiving faces of a plurality of photoelectric conversion means in different luminous quantities to extend the dynamic range of incidence luminous strength.

The device is mounted with 1st and 2nd linear CCD image sensors (line sensors) 31, 32 whose characteristics are equal to each other as photoelectric conversion means. Furthermore, a beam splitter 22 acting as an optical path branch means a placed to an image forming side of a lens 21. The beam splitter 22 splits an object light L being an image light transmitted through the lens 21 into 1st and 2nd object lights L1, L2 whose luminous quantity differs. A signal processing circuit 40 selects alternatively obtained image pickup information as valid information and corrects data in response to a ratio of the luminous quantities shared by the line sensors 31, 32.