To perform a course change such as traffic law obeying passing by connecting a separately arranged turn signal lamp in parallel through a delay circuit, and arranging a color of this separately arranged turn signal lamp as a separate color from the other turn signal lamp.

For example, a green turn signal lamp 5 is connected in parallel through a delay circuit 6 separately from a yellow turn signal lamp 3. Delay time of the delay circuit 6 is set to three seconds. When a turn signal switch 2 is turned on, a battery 1 supplies an electric current to the turn signal lamps 3, 5 through an intermittent current carrying circuit 4. The turn signal lamp 3 starts flashing by this electric current supply, but one turn signal lamp 5 starts flashing after three seconds since the delay circuit 6 delays electric current supply. Therefore, passing can be performed after turn signal lamp flashing of accurate three seconds according to traffic laws.