PROBLEM TO BE SOLVED: To detect the presence / absence information of a subject to be detected for conductivity and to measure a biological signal in an environment in which a conductive signal shield is interposed between a sensor unit and a subject. A sensor device (400) includes a signal transmission unit (406) that transmits an inspection signal according to the approach and operation of a subject (404), and a sensor unit (402) that detects the transmitted inspection signal. A measurement unit (407) that measures and stores the detected inspection signal as a response signal indicating a capacitance value, and a power supply unit (401) that supplies power to the measurement unit are included. The signal transmission unit (406) is not connected to the ground, and the signal transmission unit (405) with respect to the conductor (405) as a signal shield interposed between the subject (404) and the sensor unit (402). The first portion (408) of the 406) is arranged closer to the sensor portion (402) than the conductor (405), and the second portion (409) of the signal transmission portion (406) is the conductor (405). It is located closer to the subject (404). [Selection diagram] Fig. 4【課題】センサ部と被検者との間に導電性の信号遮蔽体が介在する環境において、導電性の検出対象である被検者の存否情報の検出や生体信号の計測を行う。【解決手段】センサ装置（４００）は、被検者（４０４）の接近および動作に応じた検査信号を伝達する信号伝達部（４０６）と、伝達された検査信号を検知するセンサ部（４０２）と、検知された検査信号を静電容量値を示す応答信号として計測し記憶する測定部（４０７）と、前記測定部に電源を供給する電源部（４０１）とを含む。信号伝達部（４０６）は接地接続されておらず、被検者（４０４）とセンサ部（４０２）との間に介在する信号遮蔽体としての導電体（４０５）に対して、信号伝達部（４０６）の第１の部分（４０８）が導電体（４０５）よりセンサ部（４０２）の近傍に配置されており、信号伝達部（４０６）の第２の部分（４０９）が導電体（４０５）より被検者（４０４）の近傍に配置されている。【選択図】図４
