A light source apparatus, in which an energy beam transforms a liquid raw material into plasma to extract radiation, includes a rotation body, a raw material supply section, and a layer thickness adjustment section. The rotation body is disposed at a position onto which the energy beam is incident, and includes a groove overlapping with an incident area of the energy beam. The raw material supply section supplies the groove with the liquid raw material. The layer thickness adjustment section adjusts a layer thickness of the liquid raw material such that a front surface of the liquid raw material forms a concave surface in response to the groove in the incident area of the energy beam.