PROBLEM TO BE SOLVED: To provide a measurement device which makes it possible to know the behavior of ion species in detail.SOLUTION: A measurement device includes a measurement unit for applying m (where m is an integer greater than or equal to n) different input signals including n (where n is an integer greater than or equal to 2) frequency components to an object under measurement and acquiring m response signals, and an analysis unit for calculating a nonlinear impedance from the m input signals and m response signals.【課題】イオン種の挙動をより詳細に知ることができる計測装置を提供する。 【解決手段】計測装置は、ｎ個（ｎ：２以上の整数）の周波数成分を含む、異なるｍ個（ｍ：ｎ以上の整数）の入力信号を被計測物に与え、ｍ個の応答信号を取得する測定部と、ｍ個の入力信号およびｍ個の応答信号から、非線形インピーダンスを算出する解析部とを含んでいる。【選択図】図１３
