There is provided a photoelectric conversion apparatus which is characterized by comprising a plurality of photoelectric conversion regions of a first conductivity type, and a plurality of semiconductor regions of a second conductivity type opposite to the first conductivity type; and in that the plurality of photoelectric conversion regions of the first conductivity type and the plurality of semiconductor regions are alternately arranged, and a voltage controlling unit is further provided to change a width of a depletion layer formed in a semiconductor substrate by controlling a voltage to be applied to the semiconductor region of the second conductivity type provided between the plurality of photoelectric conversion regions of the first conductivity type.