Patent ID: 7203536

Claim:
A bioelectrical impedance measurement method for measuring bioelectrical impedance relating to information about an inside of a limited part of a living body from an electrical signal measured on a substantially flat surface of the living body, having: a first measurement mode where a set of current-carrying electrodes including a first electrode and a second electrode for being attached to the surface of the living body set apart from each other at predetermined distances to generate a flow of radio frequency current in the living body between the first electrode and the second electrode, the first electrode having a smaller contact area than the second electrode; and a second measurement mode where a flow of radio frequency current is generated between the second electrode and a third electrode for being attached to the surface of the living body on an extension of a straight line drawn between the first electrode and the second electrode, where the extension is made beyond the first electrode, and the method comprising: measuring a voltage on the surface of the living body between a part adjacent to the first electrode and a contact part of the second electrode for each of the first and second measurement modes, and calculating a voltage difference between the two modes; and calculating the bioelectrical impedance in a depth direction below a contact part of the first electrode, based on the voltage difference and a value of the radio frequency current.