A light source apparatus includes first and second light sources having different maximum light amounts used, a first light amount detection section detecting a light amount of first light of the first light source, a second light amount detection section detecting a light amount of second light of the second light source, a light amount limiting section limiting a light amount of light incident upon the second light amount detection section so that light amounts detected in the first light amount detection section and the second light amount detection section match a predetermined value within a detection range when light with the maximum light amounts used are emitted from the first light source and the second light source, and a control section controlling amounts of light emission of the first light source and the second light source based on detection results of the first and second light amount detection sections.