ALARM FOR KEY CARELESSLY LEFT IN KEY HOLE

PURPOSE:To announce an alarm certainly for an engine key carelessly left in its key hole by means of a simple structure utilizing existent circuits, by forming a series circuit with a door switch, a key switch key a switch and an alarm so as to supply power in form of electric current for driving a door lock actuator. CONSTITUTION:When a door is opened with an ignition switch 3 in off position and a lock switch 13 is put in ON position by means of lock operation, a controller 15 puts a relay R1 in ON position by means of timer TM for a certain time via a transistor T1 and supplies power to an actuator 16 so as to effect concentration lock. Then, if a key is carelessly left in the key hole with a key switch 7 in ON position, electric current flowing out form a relya R1 flows through the key switch 7, an alarm buzzer 6, a door switch 5 and an electric appliance load and operates the alarm buzzer 6 for a period of time of a timer. Thus, a simple structure, using existent circuits can announce an alarm certainly for an engine key carelessly left in its hole.