PURPOSE: To rapidly and accurately detect partial disconnection in a line and a plated through-hole by providing a means forcibly raising and lowering the temp. of a printed wiring board and a continuity inspecting means for inspecting the continuity between the arbitrary points of a circuit on the printed board.

CONSTITUTION: A valve 3 and a low temp. tank 4 both of which supply low temp. air and a valve 5 and a high temp. tank 6 both of which supply high temp. air are connected to a table 2 on which a printed wiring board 1 is placed and, further, a plurality of spring pins 7 supplying inspection currents between the arbitrary points of the circuit on the wiring board 1 and a continuity inspecting part 8 are provided. When the wiring board 1 is set to a low or high temp. state, judging lines 10, 13 become perfect disconnection states 10a, 13a by the difference of thermal expansion between a line 9 and the wiring board 1 or a base material 1 and a plated copper through-hole and, when an inspection current is preliminarily supplied thereto, the inspecting part 8 detects the presence of partial disconnection. By this method, the presence of partial disconnection can be detected accurately and rapidly.