There is provided a test apparatus for testing a device under test, including a test signal generator that generates a test signal to test the device under test, an electric-photo converter that converts the test signal into an optical test signal, an optical interface that (i) transmits the optical test signal generated by the electric-photo converter to an optical receiver of the device under test and (ii) receives and outputs an optical response signal output from the device under test, a photo-electric converter that converts the optical response signal output from the optical interface into an electrical response signal and transmits the electrical response signal, and a signal receiver that receives the response signal transmitted from the photo-electric converter and a test method.