A solid-state imaging device contains a photoelectric part in which a plurality of picture elements each consisting of a photodiode and a switching transistor are arranged in two dimensions. The picture elements are disposed on the same semiconductor substrate, and scanning circuits which scan the switching transistors of the photoelectric part in succession are provided. The solid-state imaging device further comprises a semiconductor layer which has a conductivity type opposite to that of the semiconductor substrate and which is disposed in one major surface of the semiconductor substrate and means for applying a reverse bias between the semiconductor layer and the semiconductor substrate. At least the photoelectric part is disposed within the semiconductor layer, and a high impurity concentration region which has the same conductivity type as that of the semiconductor layer and is disposed at least under a part of the photodiode.