The object of the present invention is to solve problems treatment time when using an SLS method or continuous-oscillation laser. An indispensable portion is scanned with a laser beam in order to crystallize a semiconductor film by driving a laser and so on in accordance with the positions of islands instead of scanning and irradiating the whole semiconductor film. The present invention makes it possible to omit the time for irradiating a portion to be removed through patterning after crystallizing the semiconductor film with a laser beam and greatly shorten the treatment time for one substrate.