PURPOSE: To improve serviceability, by locating a power outlet for accessory part use only seperately from an outlet for cigarette lighter connector, and by allowing the power outlet and a power battery to be connected together by means of a key switch.
CONSTITUTION: When an engine switch 2 is turned on, a contact point 4b is closed as a result of an electric current is supplied to a coil 4a of a relay 4. The voltage of a power battery 1 is then impressed to terminals 5a and 5b of a power outlet 5. Thus, when their respective terminals 5a, 5b and 10c, 10d are electrically connected by inserting into the outlet 5 a plug 10 of an accessory part 11, such as an electric pot, an electric blanket, etc., the electric part 11 starts to work as a result of the battery voltage being impressed thereto. Now, the arrangement in a T-shape of their respective terminals 5a, 5b and 10c, 10d may lead to keep the accessory part 11 from beakage caused due to a wrong connection of a positive and a negative polarity.