A light source apparatus includes an excitation light emitter configured to irradiate excitation light, a phosphor that receives the excitation light and converts the excitation light into wavelength band light different from the excitation light, and a color wheel device. A first region of regions divided in a radial direction of the color wheel device includes a first transparent part that transmits the wavelength band light. A second region, which is different from the first region of the regions divided in the radial direction of the color wheel device, includes a reflector that reflects the excitation light and changes a light path and a second transparent part that transmits the excitation light. The phosphor is arranged on a light path of the excitation light reflected by the reflector or on a light path of the excitation light transmitted by the second transparent part.