A photoelectric conversion device, having a horizontally long rectangular shape, comprising: a pixel block in which a plurality of pixels are arranged; a plurality of signal processing blocks (20A - 20Z), arranged in parallel along a vertical direction of the photoelectric conversion device, configured to process a signal output from the pixel block; a power source voltage supply block configured to supply a power source voltage to the pixel block and the plurality of signal processing blocks (20A - 20Z); and an electrode pad connected to the power source voltage supply block, wherein each of the plurality of pixels includes a photoelectric conversion element configured to perform a photoelectric conversion in accordance with an incident light, and an electric charge/voltage conversion unit, including a first amplifier, configured to convert an electric charge, converted from the incident light, into an electric voltage, wherein in the pixel block, a plurality of columns are arranged in parallel along a longitudinal direction of the photoelectric conversion device, each column being set as a unit of signal processing including a predetermined number of pixels, as a whole entity, wherein a plurality of vertical power feeding wirings that enable the power source voltage, output from the power source voltage supply block, to be fed to each of the plurality of columns of the pixel block, from the vertical direction, are arranged, wherein a plurality of horizontal power feeding wirings that enable the power source voltage, output from the power source voltage supply block, to be fed to the pixel block and the plurality of signal processing blocks (20A - 20Z), from the longitudinal direction, are arranged, wherein the plurality of vertical power feeding wirings and the plurality of horizontal power feeding wirings are connected to each other, and wherein the pixel block, the signal processing blocks (20A - 20Z), the power source voltage supply block, and the electrode pad are arrayed in this order from the top to the bottom in the vertical direction. a pixel block in which a plurality of pixels are arranged; a plurality of signal processing blocks (20A - 20Z), arranged in parallel along a vertical direction of the photoelectric conversion device, configured to process a signal output from the pixel block; a power source voltage supply block configured to supply a power source voltage to the pixel block and the plurality of signal processing blocks (20A - 20Z); and an electrode pad connected to the power source voltage supply block, wherein each of the plurality of pixels includes a photoelectric conversion element configured to perform a photoelectric conversion in accordance with an incident light, and an electric charge/voltage conversion unit, including a first amplifier, configured to convert an electric charge, converted from the incident light, into an electric voltage, wherein in the pixel block, a plurality of columns are arranged in parallel along a longitudinal direction of the photoelectric conversion device, each column being set as a unit of signal processing including a predetermined number of pixels, as a whole entity, wherein a plurality of vertical power feeding wirings that enable the power source voltage, output from the power source voltage supply block, to be fed to each of the plurality of columns of the pixel block, from the vertical direction, are arranged, wherein a plurality of horizontal power feeding wirings that enable the power source voltage, output from the power source voltage supply block, to be fed to the pixel block and the plurality of signal processing blocks (20A - 20Z), from the longitudinal direction, are arranged, wherein the plurality of vertical power feeding wirings and the plurality of horizontal power feeding wirings are connected to each other, and wherein the pixel block, the signal processing blocks (20A - 20Z), the power source voltage supply block, and the electrode pad are arrayed in this order from the top to the bottom in the vertical direction.