To provide a light source device capable of aiming at higher brightness of a light source by efficiently radiating heat of light emitting elements.

The light source device is provided with light emitting elements 1, a heat radiation component 3 for radiating heat of the light emitting elements, a cooling fan 5 having blades 14 for cooling the heat radiation component, and a heat conduction means conducting heat of the light emitting elements to the blades of the cooling fan through the heat radiation components, and making the blades function as a heat sink. The heat conduction means is composed of a heat conduction material 8 with a recess 17 formed on the other surface 3b of the heat radiation component, with a head 10 of a roller 12 inserted into the recess in free rotation, and filled in a gap formed between a bottom surface 17a of the recess and a top surface 10a of the head.