A support determination unit prohibits a driving support ECU from performing a driving support control in the situation where an axis tilt error has not been not confirmed yet, when an axis tilt state detection unit detects an axis tilt state of a radar. The support determination unit cancels prohibiting the driving support ECU from performing the driving support control, when the radar axis tilt state has disappeared before a predetermined time period elapses, the predetermined time period being a time period within which a cause for a temporary axis tilt state is expected to be removed.