A testing apparatus including a plurality of testing module slots to which different types of testing modules for testing a device under test are optionally mounted, includes an operation order holding unit for holding information indicating that a test operation by a first testing module should be performed before a test operation by a second testing module, a trigger return signal receiving unit for receiving a trigger return signal from the first testing module, the trigger return signal indicating that the first testing module has completed the test operation thereof, when the test operation of the first testing module has been completed, and a trigger signal supplying unit for supplying a trigger signal to the second testing module, the trigger signal indicating that the second testing module should start the test operation thereof, when the trigger return signal receiving unit receives the trigger return signal.