PROBLEM TO BE SOLVED: To provide a bio-impedance meter for appropriately detecting an abnormal condition caused by the influence of a contact impedance.SOLUTION: The bio-impedance meter includes a constant electric current portion 20 for applying a predetermined alternating current within the range of maximum supply voltage to a living body 900 through electrodes 1 and 2, and a voltage measuring portion 21 for measuring a fall voltage caused by the current flowing in the living body, through electrodes 3 and 4. The voltage measuring portion 21 includes a differential amplifier circuit 22 for inputting and differentially amplifying the fall voltage within the range of maximum input voltage. When the supply voltage to the electrode 1 or electrode 2 from the constant electric current portion 20, exceeds the range of allowable supply voltage set within the range of maximum supply voltage, or when the input voltage to the differential amplifier circuit 33 from a third electrode 3 or fourth electrode 4, exceeds the range of allowable input voltage set within the range of maximum input voltage, an error detecting portion 40 determines contact error between the living body 900 and the electrode 1, 2, 3, or 4.COPYRIGHT: (C)2013,JPO&INPIT【課題】接触インピーダンスの影響による異常を適切に検出できる生体インピーダンス測定装置を提供すること。【解決手段】電極1,2を介して最大供給電圧範囲内で生体900に所定の交流電流を流す定電流部20と、生体に通電電流が流れることにより生じた降下電圧を、電極3,4を介して測定する電圧測定部21とを備える。電圧測定部21は、降下電圧を最大入力電圧範囲内で入力して差動増幅する差動増幅回路22を含む。定電流部20からの電極1若しくは電極2に対する供給電圧が最大供給電圧範囲内に設定された許容供給電圧範囲を超えたとき、または第3電極3若しくは第4電極4からの差動増幅回路33への入力電圧が最大入力電圧範囲内に設定された許容入力電圧範囲を超えたとき、エラー検知部40は生体900と電極1,2,3,4との間に接触エラーがあると判定する。【選択図】図1
