Abstract: There are provided a biological signal measurement device capable of obtaining a variety of biological information and applicable also to medical fields and the like, a biological state inference device, and a biological state inference system using these. The biological signal measurement device 1 of the present invention includes three biological signal detection units, namely, a left upper part biological signal detection unit 11, a right upper part biological signal detection unit 12, and a lower part biological signal detection unit 13. The biological state inference device 1 is capable of obtaining a highly precise inference-use processed waveform from which electrical noise has been removed, by using an appropriate combination of time-series data obtained from the three biological signal detection units 11 to 13.

Abstract: Blood pressure is estimated in a non-constraining manner continuously and in real time. A biological signal collected from a person's dorsal part is analyzed, vibration in the human body ascribable to a blood flow rate change in a period from the ventricular filling period to the isovolumetric systole is captured, and the state of fluctuation of an index indicating the state of the in vivo vibration is further captured. This fluctuation index correlates with a person's blood pressure. Therefore, it is possible to estimate whether the blood pressure is in a range indicating a normal-range blood pressure or in a range indicating a high blood pressure, only by having the person sit or lie supine on a surface provided with a biological signal measurement device to measure a biological signal in a non-constraining manner, so as to make the biological signal measurement device contiguous with the person's dorsal part.

Abstract: The present invention uses a time-series waveform of biosignal information collected from the back of a person and including biological sound and vibration (back body surface pulse wave). The back body surface pulse wave is pressure vibration arising from cardiac and aortic motions, and includes ventricular systolic and diastolic information and information on vascular wall elasticity which serves as an auxiliary pump for the circulation, and is considered as a vibration system including both the damping of viscous damping friction and the damping of solid friction. The back body surface pulse wave fluctuates according to a flow rate (stroke volume) of blood pumped out from the heart, and the fluctuation of this flow rate is reflected in the amplitude of the time-series waveform of the back body surface pulse wave.