A semiconductor device is manufactured through steps in which a photoelectric conversion element and an amplifier circuit are formed over a first substrate with a release layer interposed therebetween, and the photoelectric conversion element and the amplifier circuit are separated from the first substrate. Output characteristics of the amplifier circuit are improved and the semiconductor device with high reliability is obtained. A manufacturing method of such semiconductor device includes steps of forming a metal layer having an opening portion over a substrate, forming an insulating layer over the entire surface of the substrate including the opening portion and the metal layer, forming a photoelectric conversion layer in a region which overlaps with the metal layer and is a layer over the insulating layer, forming an amplifier circuit, which amplifies an output current of the photoelectric conversion element by using a thin film transistor, in the opening portion in the metal layer, forming a protective layer over the photoelectric conversion element and the amplifier circuit, and separating the photoelectric conversion element and the amplifier circuit, together with the insulating layer, from the substrate through laser irradiation to the metal layer.