A photoelectric conversion element, comprising: a depletion-layer extension-promotion region (10a, 11) having an upper layer of a first conductivity type; a photoelectric conversion layer of the first conductivity type in contact with the upper layer of the depletion-layer extension-promotion region (10a, 11), having a lower impurity concentration than the upper layer; a surface-buried region of a second conductivity type buried in a part of an upper portion of the photoelectric conversion layer, configured to implement a photodiode together with the photoelectric conversion layer; a well region (14a, 14b, 14c) of the first conductivity type buried in another part of the upper portion of the photoelectric conversion layer, having higher impurity concentration than the photoelectric conversion layer; a charge-accumulation region of the second conductivity type buried in a part of an upper portion of the well region (14a, 14b, 14c), configured to accumulate signal charges temporally; a plurality of intra-pixel circuit-elements merged in a part of the well region (14a, 14b, 14c), configured to implement a circuit for reading out the signal charges from the charge-accumulation region; and an injection-blocking element (13b, 13d) having a tab-region of the second conductivity type dividing the well region (14a, 14b, 14c) into no less than two at least at a part of the well region (14a, 14b, 14c), configured to block injection of non-signal charges having opposite conductivity type to the signal charges from the well region (14a, 14b, 14c) into the photoelectric conversion layer by a potential profile generated by a junction between the tab-region of the second conductivity type and the well region of the first conductivity type, wherein an entire range intended as a signal-charge generation-region in the photoelectric conversion layer is depleted by a voltage applied to the upper layer, with aid of the relative impurity concentrations of the photoelectric conversion layer and the upper layer. a depletion-layer extension-promotion region (10a, 11) having an upper layer of a first conductivity type; a photoelectric conversion layer of the first conductivity type in contact with the upper layer of the depletion-layer extension-promotion region (10a, 11), having a lower impurity concentration than the upper layer; a surface-buried region of a second conductivity type buried in a part of an upper portion of the photoelectric conversion layer, configured to implement a photodiode together with the photoelectric conversion layer; a well region (14a, 14b, 14c) of the first conductivity type buried in another part of the upper portion of the photoelectric conversion layer, having higher impurity concentration than the photoelectric conversion layer; a charge-accumulation region of the second conductivity type buried in a part of an upper portion of the well region (14a, 14b, 14c), configured to accumulate signal charges temporally; a plurality of intra-pixel circuit-elements merged in a part of the well region (14a, 14b, 14c), configured to implement a circuit for reading out the signal charges from the charge-accumulation region; and an injection-blocking element (13b, 13d) having a tab-region of the second conductivity type dividing the well region (14a, 14b, 14c) into no less than two at least at a part of the well region (14a, 14b, 14c), configured to block injection of non-signal charges having opposite conductivity type to the signal charges from the well region (14a, 14b, 14c) into the photoelectric conversion layer by a potential profile generated by a junction between the tab-region of the second conductivity type and the well region of the first conductivity type, wherein an entire range intended as a signal-charge generation-region in the photoelectric conversion layer is depleted by a voltage applied to the upper layer, with aid of the relative impurity concentrations of the photoelectric conversion layer and the upper layer.