PURPOSE: A semiconductor element testing device is provided to reinforce connectivity between a device under test (DUT) board and the contact pint of a socket by combining the DUT board with the socket. CONSTITUTION: A coupling unit (100) comprises a protrusion part (120) constructing a center line; a pair of side walls (130) forming both side walls; and a hook (110) formed at the side wall. A plate including the protrusion part is connected to a DUT board (30) with an elastic force. When the protrusion part compresses the DUT board, the DUT board compresses a part in which the contact pin of the socket is located. The DUT board is electrically connected to a base (20). [Reference numerals] (AA) Strabismus view; (BB) Side view
