Probing test apparatus

A probing test apparatus for testing electric properties of a circuit while sending a test signal to the circuit to be tested, comprising:

• a probe card having a plurality of probes and first terminals to be contacted with and to be electrically connected to conductive pads of the circuit to be tested;
• a test head having a signal transmitting circuit through which the test signal is transmitted to each of the probes;
• a performance board having second terminals electrically connected to said signal transmitting circuit of the test head;
• a contact ring interposed between the performance board and the probe card and whose impedance has been adjusted;
• a plurality of first-type pogopins each having a pair of pin members contacting the first and second terminals to transmit the test signal to each of the probes said first-type pogopins being arranged in the contact ring;
• and
• a plurality of second-type pogopins each having a pair of pin members contacting the first and second terminals, said second-type pogopins being arranged in the contact ring, and spaced from said first-type pogopins in a plane perpendicular to the axes of said pin members, said second-type pogopins electrically grounded,
• wherein an interval L.sub.1 in the plane between each of the first-type pogopins and some of the second-type pogopins which are the nearest to said each of the first-type pogopins is smaller than an interval L.sub.2 in the plane between said each of the first-type pogopins and an adjacent first-type pogopin which is the nearest to said each of the first-type pogopins,
• and wherein for each one of said first-type pogopins the closest pogopins thereto in said plane are all second-type pogopins such that said one of said first-type pogopins is surrounded by said second type pogopins.