[Object] External leakage of laser light can be prevented in a reflective type light source device.[Solution] Laser light excites a first surface (21) of a phosphor light-emitting section. (20), and a window portion (30) formed of a transparent member disposed spaced away from the first surface (21) is provided. A light leakage prevention portion (600), which inhibits the laser light reflected at the first surface (21) of the phosphor light-emitting section (20) from leaking to the outside through the window portion (30) is provided to part of the window portion (30).