An apparatus for testing a semiconductor integrated circuit includes a plurality of probe lines and a plurality of sense lines which intersect each other to thereby define a plurality of intersections thereby as electrically isolated from each other. An electronic switch device is provided for each intersection for producing a multilevel signal, on an associated sense line, having one of a predetermined number of voltage levels corresponding to various combinations definable by a predetermined number of binary numbers supplied to test points from logic elements to be tested.In a four test point embodiment, four test points are arranged such that each test point is located in a corresponding one of four quadrants defined by a pair of probe and sense lines intersecting each other. Preferably, the integrated circuit is in the form of a gate array.