It is an object of the present invention to control the position in crystal lateral growth of a semiconductor film without making a system cumbersome and complicated.A method for manufacturing a semiconductor device according to the present invention includes the step of forming a semiconductor film over an insulating substrate, forming a reflective film comprising an insulating film on the semiconductor film, exposing a portion of the semiconductor film by patterning of the reflective film, and crystallizing the exposed semiconductor film by irradiating the exposed semiconductor film with laser light while using the patterned reflective film as a mask. In the above-described method according to the present invention, the reflective film has a structure in which an insulating film that has a higher refractive index and an insulating film that has a lower refractive index are stacked alternately.