The present invention provides an apparatus for measuring activity signals of a biological sample comprising: a measurement chamber (A) storing a target liquid containing a biological sample; a porous insulating substrate (5) provided with a measurement electrode (1) on at least one side; and a conveying device (8) which conveys the target liquid stored in the measurement chamber (A) and passes the target liquid through the porous insulating substrate (5) from the measurement electrode (1) side, wherein the conveying device (8) is operated to trap the biological sample contained in the target liquid onto the measurement electrode (1), so that the activity signals of the biological sample are measured through the measurement electrode (1). According to the apparatus, activity signals emitted from the biological sample can be detected easily, rapidly and accurately.