PURPOSE: To increase an effective opening rate of a pickup region, by forming a focusing lens consisting of a lens group with plural steps which have curvature radii varied gradually at every step from the center to the periphery of each infrared ray detecting section to enable to focus infrared rays into the center, at the back face on which infrared rays are incident.

CONSTITUTION: At each position corresponding to each infrared ray detecting section 1, on the back face of a semiconductor substrate 6 on which infrared rays are incident, a focusing lens 15 consisting of a plural ring lens group being a kind of Fresnel lens is formed with etching. The focusing lens 15 centers a piccell of each infrared ray detecting section 1, that is, the center of Schottky junction 7 side, and has curvature radii varied gradually at every step from the center to the periphery, that is, respective gate electrode 9, 11 sides of a transfer gate 4 and a vertical shift-register 2, enabling to focus infrared rays into the center. Using the focusing lens 15 so constructed, incident rays into light non-sensing regions B such as the transfer gate and vertical shift-register as well as incident rays into the effective light sensing region A can be focused and incident into the infrared ray detecting section 1.