Light source housing, light source device, and image projection apparatus

A light source housing to which a light source lamp having a light emission tube and a reflector is attached, the light source housing comprising:

• a pair of flow paths bifurcating onto upper and lower sides of the light emission tube from an air intake port for introducing a cooling air;
• a flow path open and close unit including a plate that slides in a direction of the gravitational force so as to open the flow path on the upper side of the light emission tube and close the flow path on the lower side of the light emission tube, said direction of the gravitational force being perpendicular to the flow path and the plate being arranged so that a surface of the plate being parallel to the gravitational force so that the direction of the gravitational force is parallel to the surface of the plate;
• and
• an air outtake port that outtakes the cooling air introduced into the reflector from the flow path on the upper side of the light emission tube to an outside of the reflector.