To provide a light source device with a mechanism for preventing scattering of the broken pieces of a bulb capable of detecting also the breakage mode of a bulb in such an extent that a reflector is not broken and closing an exhaust port.

The light source device with the mechanism for preventing the scattering of the broken pieces of the bulb is equipped with a lamp 11 comprising the bulb 20 and the reflector 30, a light transmissive plate 41, a lamp house 50 provided with an air feed port 32 and the exhaust port 53 forming the path of air for cooling inside and constituted of an upper lamp house 52 and a lower lamp house 51, and the mechanism 60 for preventing the scattering of the broken pieces of the bulb. The mechanism 60 for preventing the scattering of the broken pieces of the bulb has an exhaust port shutter 54 capable of closing and opening the exhaust port 53 of the lamp house 50 and biased toward a closing position by a spring 56, and a bulb abnormality detection wire 61 whose one end is fixed near the edge of the bulb 20 on the aperture part side of the reflector 30 and whose other end holds the stopper 66 of the exhaust port shutter 54 so that the exhaust port shutter 54 is present at an opening position against the biasing force of the spring 56.