A housing holder is provided with detectors to be inserted into communication grooves of a connector. The detectors are electrically connected through a lead wire to a test device. The test device is also connected to an adapter electrically connected to a rear end of a probe on each terminal. During a continuity test, incomplete insertion or dropout of a terminal, and a short circuit between terminals are detected by comparing a circuitry formed by a contact of each terminal with the detector and probe with a circuitry stored in the memory of the test device beforehand. |