A light source apparatus is provided which uses a plurality of semiconductor laser devices and which offers adequate heat dissipation. The light source apparatus using a plurality of semiconductor laser devices includes a holding member on which the plurality of semiconductor laser devices is arranged, wherein at least one semiconductor laser device among the plurality of semiconductor laser devices is arranged on the holding member such that a relative position of the semiconductor laser device in an optical axis direction with respect to an adjacent semiconductor laser device in a front view of the holding member is greater than a relative position of the semiconductor laser device in a direction perpendicular to the optical axis direction with respect to the adjacent semiconductor laser device.