Abstract: A flasher apparatus for vehicles capable of protecting from a short-circuit failure. A relay switch is connected in series with an electric power source and direction indicating lamps so that the lamps are energized periodically by the closure of the switch activated by the periodic conduction of an output transistor of an oscillator circuit. A short-circuit detector circuit detects an electric current flowing to the lamps and prevents the output transistor from being rendered conductive in response to the large value of the electric current. The output transistor is allowed to be rendered conductive when a rush current flows to the lamps.