Provided is a test apparatus that tests a device under test, comprising a phase comparing section that compares a phase of an internal clock generated in the test apparatus and a phase of a clock superimposed on a device signal output by the device under test; an adjusting section that adjusts a phase shift amount of the internal clock with respect to the device signal, based on the phase comparison result; an acquiring section that acquires the device signal according to the internal clock whose phase shift amount with respect to the device signal is adjusted; and an inhibiting section that inhibits change of the phase shift amount based on the phase comparison result, for at least a portion of a period during which the clock is not superimposed on the device signal. Also provided is a test method relating to the test apparatus.