An electrode pad for use on a living organism can measure an electrocardiographic signal without being hindered by body-motion noise. The electrode pad is attached to the skin of the living organism, detects an electrical signal, and supplies the electrical signal to an electrocardiograph. The electrode pad for use on a living organism is characterized by the provision of a mesh-like electrode that extends along the skin, a conductive gel sheet that is layered on top of the electrode and extends along the surface of the skin, and a soft protective sheet that covers the layered electrode and conductive gel sheet.