Device for giving alarm for failure to draw out key for vehicle

A device for giving an alarm for failure to draw out a key for a vehicle, comprising:

• a key cylinder lock for the vehicle including an outer tubular member having axially spaced penetrating holes (3, 4) therein, and an inner tubular member rotatably provided within said outer tubular member and having grooves (6) therein corresponding with said holes (3, 4) in said outer tubular member,
• a plurality of magnet pin tumbler inserts each serving as a movable obstruction element accommodated within both the holes (3, 4) of the outer tubular member and the grooves (6) of the inner tubular member,
• a switch member provided in each hole (3, 4) in said outer tubular member, which switch member is turned on by said magnet tumbler inserts when a magnet key is inserted into a keyhole (8) in said inner tubular member in which the turned on switch member completes an electrical circuit with a power supply delivered from a battery mounted in said vehicle,
• a door switch in said electrical circuit which is turned on when a door of said vehicle is opened, and
• an alarm unit connected to both said door switch and said switch member in each hole and operative to produce an alarm when the door of the vehicle is opened under a condition where the magnet key is inserted within the key hole at the time the door is opened.