The present invention is directed to adjusting a light intensity distribution on an irradiation target surface into a desired distribution with use of a light source apparatus including a light emitting diode (LED) array. A light source apparatus includes an LED array including a plurality of LED chips, and a controller configured to control the plurality of LED chips. A light intensity distribution acquired from each of the plurality of LED chips is superimposed on a light intensity distribution oriented in a different direction from each other on a predetermined surface. The controller controls an output of at least one of the plurality of LED chips, thereby changing the light intensity distribution that the plurality of LED chips forms on the predetermined surface.