arranged in the optical path of the laser beam is not limited in particular for example when the laser oscillation device 103 is provided above the substrate 100 and is arranged so that the laser beam emitted from the laser oscillation device 103 is perpendicular to a substrate surface a reflecting mirror is not necessarily used in addition as each optical system a collective lens a beam expander a homogenizer a polarizer a slit or the like may be used or these may be combined with each other by two dimensionally scanning the irradiation region of the laser beam on a surface to be irradiated as appropriate irradiation is performed on a large area of a substrate in order to perform scanning the irradiation region of the laser beam and the substrate are relatively moved here scanning is performed with moving means not shown for moving a substrate stage 109 which holds the substrate in x and y directions it is preferable that the control device 116 be interlocked so as to control the moving means for moving the substrate stage 109 in the x and y directions in addition it is preferable that the control device 116 be interlocked so as to control the laser oscillation device 103 furthermore it is preferable that the control device 116 be interlocked with a position.