To provide a light source device which does not prevent cooling at normal use, completely completely trapping fragments inside the lighting device in case of the explosion of a lamp.
A vent hole 24 for cooling the lamp 12 and an another opening 26 independent from the vent hole 24 are formed at an exchanging side of a lamp housing 20 arranged so as to surround the lamp. A movable body 42 is arranged between a release position keeping away from the vent hole 24 and a blocking position blocking the vent hole 24 in free movement. A detection plate 50 receiving a pressure wave generated by the blowout of the lamp is fitted at the opening 26. The movable body 42 is moved toward the blocking position in conjunction with an operation of the detection plate 50 receiving the pressure wave.
Yoshitake Hidetoshi
Takahiro Arita