The light source apparatus includes: a light source substrate having a light emission unit; an optical sheet facing the light emission unit; a plurality of detection units configured to detect light; and an adjustment unit configured to adjust light emission brightness of the light emission unit on the basis of detection values of two or more of the detection units, the two or more detection units including the detection unit arranged at a position at which a change in the detection value due to a deflection of the optical sheet is positive when the light emission unit emits the light and the detection unit arranged at a position at which the change in the detection value due to the deflection of the optical sheet is negative when the light emission unit emits the light.