A light source apparatus includes a light source that outputs excitation light, and a rotating light emitting device in which a wavelength conversion element that emits light when irradiated with the excitation light is provided on a rotating disk. A spot of the excitation light on the wavelength conversion element has a shape that is long in a radial direction of the rotating disk and short in a circumferential direction of the rotating disk. Alternatively, an orthogonally projected length of the spot in the radial direction is greater than an orthogonally projected length of the spot in the circumferential direction.