Disclosed is a device under test (DUT) tester using a redriver. The DUT tester more effectively tests the DUT, which is a predetermined semiconductor device, by applying an electrical signal to the DUT and measuring the electrical signal. The DUT tester includes a DUT test unit, a printed circuit board (PCB) provided therein with connectors for the connection with the DUT test unit, one DUT or more horizontally arranged on the PCB, and redrivers horizontally provided under the PCB and one-to-one matched with one DUT or more to compensate for the distortion of the signal integrity of test signals caused according to the variation of the transmission distance.