Abstract: A driver circuit integrated with a load current output circuit has a function as a driver for applying a predetermined test waveform to a device under test (DUT), and a function as a load current output for reproducing an actual use situation by receiving the load current to the DUT to judge a response waveform by receiving the response waveform from the DUT. Both functions are made up on a common circuit, operate as the driver circuit when applying the test waveform, and operate as the load current output circuit when judging the response waveform.