To reduce a space in a testing apparatus occupied by a cooling section for cooling a plurality of circuit boards.

The testing apparatus for testing a device under test comprises: a test head having a plurality of circuit boards for generating a test signal applied to the device under test in accordance with an input control signal and for receiving an output signal of the device under test; the cooling section for accommodating and cooling the plurality of circuit boards; and a connecting section for interfacing signals between the device under test and the circuit boards. The cooling section comprises: a cooling case which accommodates the plurality of circuit boards and has apertures in its upper plane and lower plane; a surface side print circuit board which seals one aperture of the cooling section and interfaces signals between the plurality of circuit boards and the connecting section; a rear face side print circuit board which seals the other aperture of the cooling case and supplies control signals to the plurality of circuit boards; and a cooling medium supplying section for circulating a cooling liquid inside the cooling case.