Problem to be solved: to electrically isolate the measurement system of the biological signal and the power supply system with a simple configuration, and to improve the convenience by shortening the charging time greatly.A power supply circuit for supplying electric power to a biological signal measuring circuit configured to detect an electric signal, which is a small electric signal emitted from the human body, with an electrode in contact with the human body, and a capacitive element for accumulating the electric power and the above A circuit switching means connected between a quantity element and an external power source for supplying power to the capacitive element, and a first state in which the capacitive element and the external power supply are rendered conductive to enable charging to the capacitive element, and the capacitive element SaidThe state of the invention is configured so that the external signal and the biological signal measuring circuit are switched without being electrically connected between the external power supply and the biological signal measuring circuit in a state where the biological signal measuring circuit is rendered conductive and the power supply to the biological signal measuring circuit is enabled A circuit switching means is provided.Diagram【課題】簡易な構成で生体信号の測定系統と電源系統とを電気的に絶縁することを可能とし、また充電時間を大幅に短縮して利便性を向上させる。【解決手段】人体が発する微少な電気信号である生体信号を人体に接触させた電極で検出するように構成された生体信号測定回路に電力を供給するための電源回路であって、前記電力を蓄積するための容量素子と、前記容量素子と当該容量素子に電力を供給するための外部電源との間に接続されている回路切替手段であって、当該容量素子と前記外部電源とを導通状態として前記容量素子への充電を可能とする第1の状態と、前記容量素子と前記生体信号測定回路とを導通状態として前記生体信号測定回路への電力供給を可能とする第2の状態との間を、前記外部電源と前記生体信号測定回路との間が電気的に接続される状態を経ることなく切り替えるように構成されている回路切替手段とを備えている。【選択図】図4
