To accurately measure power source noise generated inside an integrated circuit, the power source noise measuring device comprises: a mutual inductor pair placed inside an integrated circuit, the mutual inductor pair including (i) a first inductor connected to between power source voltages of the integrated circuit and (ii) a second inductor arranged opposite the first inductor, the both ends of which second inductor are connected to external output terminals; and a power source noise measuring unit which measures power source noise of the integrated circuit on the basis of a voltage waveform output from the second inductor of said mutual inductor pair via the external output terminals.