A method of manufacturing a photoelectric conversion device, comprises forming a first insulating film on a semiconductor substrate, forming a gate electrode by forming an electrically conductive layer on the first insulating film and patterning the electrically conductive layer, etching an exposed surface of the first insulating film, forming a charge accumulation region of a photoelectric converter by implanting impurity ions of a first conductivity type into the semiconductor substrate through a thinned portion of the first insulating film formed by the etching, removing the thinned portion, forming a second insulating film covering the semiconductor substrate and the gate electrode, and forming a surface region of the photoelectric converter by implanting impurity ions of a second conductivity type opposite to the first conductivity type into the semiconductor substrate through the second insulating film.