A test apparatus includes a test head including a plurality of test boards for applying a test pattern to a device under test, a main frame for controlling a test sequence by the test head, and a fiber optic cable unit including a plurality of flat cables for optically coupling the test head and the main frame, a plurality of fiber optic cables, a dam for coupling the fiber optic cable unit and the plurality of fiber optic cables, a circumferential difference absorption apparatus for absorbing the difference in circumferential length between the plurality of flat cables of the fiber optic cable unit, and a cable guide unit for bending and holding the fiber optic cables coupled to the test board of the main frame.