An impedance measuring device, comprising: a laminated type battery, a plurality of battery cells being laminated in the laminated type battery; a first power supply unit (531 or 532) configured to output an alternating current of a prescribed frequency for measuring an impedance of the laminated type battery to a positive electrode terminal of the laminated type battery; a second power supply unit (532 or 531) configured to output an alternating current of the prescribed frequency to a negative electrode terminal of the laminated type battery; a first detection unit (521 or 522) configured to detect an alternating-current potential difference between the positive electrode terminal and an intermediate-point terminal of the laminated type battery; a second detection unit (522 or 521) configured to detect an alternating-current potential difference between the negative electrode terminal and the intermediate-point terminal; an adjustment unit configured to adjust an amplitude of the alternating current output from at least one of the first and second power supply units (531, 532) such that the alternating-current potential difference detected by the first detection unit (521 or 522) and the alternating-current potential difference detected by the second detection unit (522 or 521) coincide; and a computation unit configured to compute the impedance of the laminated type battery on the basis of the alternating current adjusted by the adjustment unit and the alternating-current potential difference; characterized by a calculation unit (561, 571, 581) configured to calculate a phase difference between an alternating-current potential generated at the positive electrode terminal and an alternating-current potential generated at the negative electrode terminal, or a parameter correlated with the phase difference; and a processing unit (600, 601) configured to perform, on the basis of the phase difference or the parameter calculated by the calculation unit, any one process of: a diagnosis process for diagnosing whether or not a measurement result is reliable; a cancellation process for discarding a measurement result; and a hold process for fixing the measurement result at a prescribed value. a laminated type battery, a plurality of battery cells being laminated in the laminated type battery; a first power supply unit (531 or 532) configured to output an alternating current of a prescribed frequency for measuring an impedance of the laminated type battery to a positive electrode terminal of the laminated type battery; a second power supply unit (532 or 531) configured to output an alternating current of the prescribed frequency to a negative electrode terminal of the laminated type battery; a first detection unit (521 or 522) configured to detect an alternating-current potential difference between the positive electrode terminal and an intermediate-point terminal of the laminated type battery; a second detection unit (522 or 521) configured to detect an alternating-current potential difference between the negative electrode terminal and the intermediate-point terminal; an adjustment unit configured to adjust an amplitude of the alternating current output from at least one of the first and second power supply units (531, 532) such that the alternating-current potential difference detected by the first detection unit (521 or 522) and the alternating-current potential difference detected by the second detection unit (522 or 521) coincide; and a computation unit configured to compute the impedance of the laminated type battery on the basis of the alternating current adjusted by the adjustment unit and the alternating-current potential difference; characterized by a calculation unit (561, 571, 581) configured to calculate a phase difference between an alternating-current potential generated at the positive electrode terminal and an alternating-current potential generated at the negative electrode terminal, or a parameter correlated with the phase difference; and a processing unit (600, 601) configured to perform, on the basis of the phase difference or the parameter calculated by the calculation unit, any one process of: a diagnosis process for diagnosing whether or not a measurement result is reliable; a cancellation process for discarding a measurement result; and a hold process for fixing the measurement result at a prescribed value.