PURPOSE: To provide a vehicle detector which manages and monitors plural sensors by one detector and has a simple constitution requiring no power sources in sensors themselves.

CONSTITUTION: Two loop antennas are electrically separated and made free from coupling, and they are coupled by approach of a metallic body. Plural sensors A1 to Az each of which consists of these two loop antennas are used, and sensors A1 to Az are made different by resonance frequencies. A frequency signal to cover the frequencies of sensors A1 to Az is supplied from an oscillator to one loop antennas of sensors A1 to Az, and reception signals of the other loop antennas of sensors A1 to Az are detected. When the metallic body like a vehicle approaches a sensor, the sensor enters into the coupling state, and the reception level of the resonance frequency of this sensor is raised. Thus, an inexpensive parking detector is provided.