Abstract: A semiconductor light exposure apparatus includes an excitation light source, a light beam generating device, a controller and a contracting optical system. The light beam generating device generates a fundamental wavelength laser light beam when excited by a light beam from the excitation light source, and wavelength-converts the fundamental wavelength laser light beam into a second harmonics laser light beam by a first resonator having a first non-linear optical crystal element while also converting the second harmonics laser light beam into a second harmonics laser light beam by a second resonator having a second non-linear optical crystal element. The controller controls an output of the excitation light source in order to control an output of the fourth-order harmonics laser light beam from the light beam generating device. The contracting optical system projects a pattern in a contracted size on a wafer by the fourth-order harmonics laser light beam outputted from the optical beam generating device.