A microcomputer of a light source control device specifies an LED belonging to LEDs and subjected to a short-circuit failure based on a result of determination by a short-circuit failure detecting circuit and current amounts sensed by current sensing circuits respectively. The microcomputer makes corresponding one of switching elements interrupt supply of a current to the specified LED. The microcomputer makes a constant current circuit supply an LED not specified with a current not exceeding a current responsive to the number of such LEDs not specified.