A light source device is provided with: a plurality of surface light sources that have different wavelength bands; a multiplexing unit that multiplexes light beams emitted from the surface light sources; and an adjustment unit that adjusts, when an endoscope that serves as a reference endoscope is connected, the light amounts of light beams emitted from the surface light sources such that illumination light emitted from the reference endoscope has a predetermined color balance and that corrects, when an arbitrary endoscope is connected, the color balance on the basis of the ratio of the color balance of illumination light emitted from the connected endoscope and the color balance of illumination light emitted from the reference endoscope.