A laser processing apparatus 1 includes: a processing light source 2 for emitting a processing light for processing a tooth 13A or a gingiva 13B; a halogen lamp 3 for emitting an illumination light for illuminating the tooth 13A or the gingiva 13B; a detector 4 capable of detecting a multiple-wavelength light from the tooth 13A or the gingiva 13B; and a controller 5 for controlling the light-emitting state of the first light-emitting part 2. The detector 4 has a first detection element 6 and a second detection element 7 with light-receiving sensitivities that differ in accordance with wavelength, detects light intensities of different wavelengths, and outputs the detection result to the controller 5. The controller 5 controls the light-emitting state of the processing light source 2 on the basis of the ratio of the respective intensities of the different wavelength light detected by the detector 4.