To provide a light source device and a projector, capable of restraining leakage of light with high output to the outside and securing its safety.

The light source device includes: an excitation light source 10 for emitting exciting light; a fluorescent layer 32 for emitting fluorescence by receiving the exciting light emitted from the excitation light source 10; a base 31 for having the fluorescent layer 32; a detection device 60 for detecting whether or not the exciting light emitted from the excitation light source 10 goes through the fluorescent layer 32 and the base 31; and a control device 70 for stopping the exciting light from emitting from the excitation light source 10 when the detection device 60 detects that the exciting light emitted from the excitation light source 10 goes through the fluorescent layer 32 and the base 31.