PROBLEM TO BE SOLVED: To provide a biological signal sensor system which accurately recognizes presence of a subject and, when the subject is present, performs measurement of biological signals.SOLUTION: The biological signal sensor system includes: a biological signal sensor formed by superposing and integrating a biological signal detection sensor on a load detection sensor； a first measurement section that measures a potential generated on a first piezoelectric sheet of the load detection sensor； a second measurement section that measures a potential generated on a second piezoelectric sheet of the biosignal detection sensor； and a control section that, when the potential measured by the first measurement part is less than a predetermined threshold, starts measurement of the potential of the second piezoelectric sheet in the second measurement section, when the second measurement section detects biological signals, outputs the signal detected by the second measurement section, and when the potential measured by the first measurement section is the predetermined threshold or more or the second measurement section detects no biological signals, performs a control not to output the signal detected by the second measurement section.
