A method for producing a semiconductor device includes irradiating an amorphous semiconductor film on an insulating material with a pulsed laser beam having a rectangular irradiation area, while scanning in a direction intersecting a longitudinal direction of the irradiation area, thereby forming a first polycrystalline semiconductor film, and irradiating a part of the amorphous semiconductor film with the laser beam, while scanning in a longitudinal direction intersecting the irradiation area, the part superposing the first polycrystalline semiconductor film and being adjacent to the first polycrystalline semiconductor film, thereby forming a second polycrystalline semiconductor film. The laser beam has a wavelength in a range from 390 nm to 640 nm, and the amorphous semiconductor film has a thickness in a range from 60 nm to 100 nm.