A light source apparatus includes: a light source that emits blue component light; a polarization adjuster that adjusts a polarization state of the blue component light emitted from the light source; a separation optical element that separates the blue component light emitted from the light source into a first optical path and a second optical path according to the polarization state adjusted by the polarization adjuster, the first optical path being for using the blue component light as excitation light, the second optical path being for using the blue component light as reference image light; a luminous body provided on the first optical path and that emits reference image light in response to the excitation light; and a combine optical element that combines the first optical path and the second optical path into a single optical path.