A light source apparatus includes a plurality of light source modules each including at least one light source unit, light guide lines connected respectively to the light source units, and a casing accommodating the plurality of light source modules and the plurality of light guide lines. The light guide lines are led from the light source units so as not to intervene in the plurality of light source modules when viewed in a direction perpendicular to an array direction of the plurality of light source modules. The plurality of light source modules are separately attachable and detachable in the direction perpendicular to the array direction of the plurality of light source modules.