PURPOSE: To obtain a automobile burglar prevention machine ensuring high burglar prevention effect, easy operability and small power consumption by enabling a warning machine to give an alarm on the basis of the detected signal of an impact sensor and a door sensor, and providing the predetermined switch part, operation part, release part and the like.

CONSTITUTION: When a power switch 21 and an automobile burglar prevention set switch 22 are turned on, an operation ready mode is set with the second relay 11 in the predetermined time. The detected signal of an impact sensor S1 or a door sensor S2 drives the first relay drive part 8 via a low frequency 2-stage amplifier 9, the second relay 11 and the like, selects the first relay 13 and actuates an alarm 1 for the predetermined time. When a driver returns to a parked automobile, a ten-key pad 14 is operated from the outside of an automobile body and an identification number keys are pressed, thereby selecting the second relay 11 via the second relay drive part 10 and making an operation part 3 inoperative.