A light source apparatus includes an arc tube having a first electrode and a second electrode that carry out an emission of light due to a discharge between them, and a drive that, when supplying energy in an alternating current to the first electrode and the second electrode, carries out a steady operation supplying a steady energy to the first electrode and the second electrode, and an initial operation making a cumulative energy supplied to at least one electrode, of the first electrode and the second electrode, in an anode period of the relevant electrode, prior to the steady period, greater than during the steady period.