In a photoelectric conversion element which is formed by alternately stacking
a region of a first conductivity type and a region of a second conductivity type
as a conductivity type opposite to the first conductivity type to form a multi-layered
structure, in which junction surfaces between the neighboring regions of the first
and second conductivity types are formed to have depths suited to photoelectrically
convert light in a plurality of different wavelength ranges, and which outputs
signals for respective wavelength ranges, a region of a conductivity type opposite
to the conductivity type of a surface-side region of the junction surface closest
to a surface is formed in the surface of the surface-side region. Thus, highly
color-separable signals which suffer less color mixture upon reading out signals
from a plurality of photodiode layers is read out.