ABNORMALITY DETECTION AND VEHICLE TRACKING DEVICE

An apparatus which senses an abnormality and setting off an alarm when an in-vehicle battery is removed, and prevents false sensing when the battery is dead is provided. The apparatus (10) that senses an abnormal state of a vehicle on the basis of a battery voltage of an in-vehicle battery (63) includes a switching means (17) for switching to an operational mode in which warning means (40) is activated when it is determined that the vehicle is in an abnormal state. When the battery voltage is reduced to a predetermined voltage within a predetermined time after an ignition SW (60) is switched off, the switching means (17) does not determine the abnormal state. When the battery voltage is reduced to the predetermined voltage after the predetermined time has elapsed, and a reduction rate of the battery voltage is higher than a predetermined value, the switching means (17) determines that the vehicle is abnormality, and switches the operational mode to an operational mode in which the warning means (40) is activated.