A light source device includes has a configuration in which a height of a heat sink from a reference surface when the reference surface is a bottom surface of a housing is set to be lower than a height of a light source unit from the reference surface, and a heat pipe includes a first heat pipe, a first end part of which is connected with the heat generation body and a second end part of which is connected with the heat sink, and a second heat pipe, a third end part of which is connected with a heat generation body and a fourth end part of which is connected with the heat sink so that a distance to the second end part is longer than a distance between the first end part and the third end part.