A test apparatus for testing a device under test includes a multi-strobe generating section that generates a plurality of strobe signals with different phases in each of cycles of an output signal output from the device under test, a plurality of timing comparing sections that obtain a value of the output signal respectively at timings of the plurality of strobe signals, a transition detecting section that generates transition data identifying one of the plurality of strobe signals which is positioned at a transition of the output signal, based on the values of the output signal which are respectively obtained at the timings of the plurality of strobe signals, a transition memory that sequentially stores thereon the transition data input thereto, a selecting section that selects, in association with each of the cycles of the output signal, whether to input the transition data output from the transition detecting section into the transition memory, and a calculating section that calculates jitter of the output signal based on the transition data stored on the transition memory.