To provide a measuring device and method capable of attaining high speed, high accuracy, and low cost without influence of noise and spurious in measuring the phase delay characteristic between an input signal and an output signal of a tested device.

This phase delay characteristic measuring device measures the phase delay of the tested device according to the phases of an input signal IF-R applied to the tested device 3 and an output signal IF-A/B from the tested device. The phase delay characteristic measuring device includes a common mode component computing means 12 for outputting an interphase value between the input sampling data of the input signal or output signal and ideal sin waveform data 13 as a base band I signal (a common mode component), an orthogonal component computing means 14 for outputting an interphase value between the input sampling data of the input signal or output signal and ideal cos waveform data 15 as a base band Q signal (an orthogonal component), a phase angle computing means for outputting the phase angles of the input signal and output signal according to the base band I signal (a common mode component) and the base band Q signal (an orthogonal component), and a phase delay computing means for computing the phase delay amount of the tested device from the phase angles of the input signal and the output signal.