A method for manufacturing a semiconductor device includes: forming a photocatalytic layer and an organic compound layer in contact with the photocatalytic layer over a substrate having a light transmitting property; forming an element forming layer over the substrate having the light transmitting property with the photocatalytic layer and the organic compound layer in contact with the photocatalytic layer interposed therebetween; and separating the element forming layer from the substrate having the light transmitting property after the photocatalytic layer is irradiated with light through the substrate having the light transmitting property.