BIOELECTRODE

There is provided a biological electrode capable of suppressing bending in the direction opposite to (inward) the direction in which a distal end side portion of an electrode portion that comes into contact with a body of a subject extends. The biological electrode 1 includes an electrode member 20 made of a conductive rubber having a plurality of electrode portions 22 in contact with a body of a subject. The plurality of electrode portions 22 are protrusively formed on an electrode portion forming surface 21b of the electrode member 20 and arranged circularly or concentrically on the electrode portion forming surface 21b. Further, each of the plurality of electrode portions 22 is formed so that a cross-sectional area thereof gradually decreases from a proximal end portion thereof toward a distal end portion thereof and a center C2 of a cross section of the distal end portion is positioned radially outward of a center C1 of a cross section of the proximal end portion as viewed from an arrangement center of the plurality of electrode portions 22.