A light source device includes: a rotating body configured to be rotated with a rotating shaft as a center； a plurality of phosphors arranged on a plurality of circumferences of different radii with the rotating shaft as the center in the rotating body, and configured to be excited by being irradiated with light and generate fluorescence； and a light source portion configured to radiate excitation light for making one phosphor arranged on a predetermined circumference among the plurality of phosphors generate the fluorescence, and configured to radiate the excitation light to an area other than a straight line passing from the rotating shaft through an irradiation position at which the one phosphor is irradiated with the excitation light, in a phosphor different from the one phosphor among the plurality of phosphors.
