To provide a light source device capable of reducing in size of the light source device in a structure having a phosphor layer, and further to provide a projector.

A light source device comprises: a first light source for emitting first light; a second light source for emitting second light different from the first light; a phosphor layer for emitting third light different from the first light and from the second light; and a wavelength selective reflecting layer for synthesizing the first light, the second light and the third light by transmitting the first light and the second light and reflecting the third light, or by reflecting the first light and the second light and transmitting the third light.