A light source apparatus of the present disclosure includes a semiconductor light source, a light source holding member on which the semiconductor light source is disposed, the light source holding member being made of a thermal conductive material, and a cooling member that radiates heat generated by the semiconductor light source through the light source holding member. In addition, the light source apparatus includes an optical lens, an optical lens holding member that holds the optical lens and that is disposed on a light-emitting portion side of the semiconductor light source, and a thermal conductive member having a hole that houses a light-emitting portion of the semiconductor light source. The thermal conductive member is sandwiched between the light source holding member and the optical lens holding member, and comes into close contact with a side surface of the light-emitting portion.