PURPOSE: To reduce smear and blooming by keeping small the extension of depletion layer toward a semiconductor substrate without excessively increasing concentration of impurity of semiconductor well forming a barrier for the flow of signal charges in the depth direction.

CONSTITUTION: An N-type semiconductor region 2 in the impurity concentration different from that of a semiconductor substrate 1 is located between a P-type semiconductor region 3 forming a barrier for the flow of photoelectrons in the depth direction and the N-type semiconductor substrate 1 and potential in the depth direction at almost the center of a photosensitive element 4 is distributed almost symmetrically in the right and left directions (shallow and deeper sides) around the dept of the top of the barrier.