A light source device includes a light emitting element adapted to emit exciting light; a fluorescent element having a phosphor and adapted to convert at least a portion of the exciting light emitted from the light emitting element into fluorescence and to reflect the fluorescence; and a common cooling member adapted to cool the light emitting element and the fluorescent element. The cooling member includes a first cooling surface coupled to the light emitting element for cooling the light emitting element, and a second cooling surface coupled to the fluorescent element for cooling the fluorescent element. The first cooling surface and the second cooling surface are placed in parallel with each other and are placed in such a way as to be oriented in the same direction.