Light source device

A light source device comprising:

• a casing including one end surface, other end surface, and one side surface between the one end surface and the other end surface;
• a light emitting unit provided on a side of the one end surface in the casing;
• a heat radiating unit provided in the casing and thermally connected to the light emitting unit;
• an exhaust port formed at least in a region located in the one side surface and facing the heat radiating unit;
• an axial fan configured to be provided in the casing and supply cooling air to the heat radiating unit;
• and
• a shielding deflecting plate configured to be provided between the axial fan and the heat radiating unit and shield a part of the cooling air supplied from the axial fan and deflect a part of the cooling air to a direction away from the exhaust port, wherein a part of the cooling air that is not deflected by the shielding deflecting plate is introduced directly into the heat radiating unit, and wherein the shielding deflecting plate is arranged to extend at an angle which is not parallel to an axial direction of the axial fan, and the shielding deflecting plate is arranged at the angle with which a direction of the cooling air toward the one end surface is deflected to a side of another side surface facing the one side surface,
• wherein the shielding deflecting plate extends from a mounting plate attached to the side of the one end surface of the axial fan, the mounting plate having an opening corresponding to an air supply port of the axial fan.