by holding the wafer 1 by means of vacuum etc the illumination means 3 and 4 form beams that are irradiated onto the wafer 1 as the illumination light source a laser light source and a lamp light source are used for the laser light source visible light ultraviolet light hereinafter referred to as uv light deep ultraviolet light hereinafter referred to as duv light vacuum ultraviolet light extreme ultra violet light etc are usable and as for a laser oscillation scheme both continuous oscillation and pulsed oscillation may be used it is preferable that the wavelength is roughly 550 nm or less and for example sources of 532 nm 355 nm 266 nm 248 nm 200 nm 193 nm 157 nm and 13 nm can be applied for the laser light source a second harmonic shg a third harmonic thg and a fourth harmonic fhg of the solid state yag laser fundamental wave wavelength 1024 nm obtained by wavelength conversion with a nonlinear optical crystal an excimer laser and an ion laser may be used moreover two different wavelengths may be resonated to oscillate another wavelength this method consists of outputting a laser light having a wavelength of 199 nm by generating a sum frequency of an shg wave wavelength 488 nm of ar laser light and a yag laser light having a wavelength of 1064 nm and establishing resonance of it as for a type of pulsed oscillation laser.