Patent ID: 7408446

Claim:
A burglar alarm device for a vehicle, comprising: a motion sensor operative to transmit a radio wave and receive the radio wave reflected in a vehicle compartment; an alarming device operative to execute alarming; and a burglar alarm control device operative to operate said alarming device for the alarming when a specified change in the reflected radio wave received by said motion sensor occurs, wherein said motion sensor is disposed so as to be located in the vehicle compartment in back of an instrument panel of the vehicle and to transmit the radio wave in a forward direction of the vehicle and toward the instrument panel, said motion sensor is provided at a rear console portion provided between front seats of the vehicle and in back of the front seats so that part of the radio wave transmitted by the motion sensor can go through a non-metal member of the front seat, the vehicle is a type of vehicle whose part of roof or entire roof are selectively opened and closed or detachable, or a type of vehicle whose roof is fixed and whose part of roof or entire roof are made of a radio-wave transmittable material, the radio wave of said motion sensor is transmitted obliquely downward with respect to a horizontal face, and there is further provided a radio-wave reflecting member operative to reflect at least part of the radio wave transmitted by said motion sensor in a direction that is off the roof of the vehicle.