Provided is a vehicle gate monitor including a gate on which a detector group is mounted, the detector group including: a first detector, which is arranged in a manner that allows vertical and horizontal movement, and is configured to measure radiation levels of both side surfaces of the vehicle; a second detector, which is arranged in a manner that allows vertical, rotational, and horizontal movement, and is configured to measure radiation levels of a front surface, a rear surface, an upper surface, and a cargo bed surface of the vehicle; and a third detector, which is arranged in a manner that allows vertical and horizontal movement, and is configured to measure a radiation level of an inner-side side surface of the cargo bed, the gate including a control unit configured to identify, while moving the gate with respect to a stationary vehicle, presence/absence of a contaminated place.