PURPOSE: To easily test a large-sized array by logically dividing a panel into areas and separately testing each area and discriminating sections which have at least one cross short-circuit.

CONSTITUTION: Under the control of a test controller 28, panel interface circuits 22 are constituted in the bypass mode, and a precise measurement unit(PMU) 26 is instructed to output a test current signal to the panel interface circuit 22 coupled to a gate line in a prescribed area. The prescribed circuit 22 relays a common test current signal from the PMU 26 to the gate line. Further, the controller 28 instructs the PMU 26 to monitor the panel interface circuit 22 coupled to a driving line in the prescribed area. When the PMU 26 detects a current in a monitored, the controller 28 indicates that this area has a defect, and smaller subareas of the defective area are tested again in a following area examination test by a series of other area separate tests.