A cellular electric potential measuring container includes a container body and an electrode substrate, the electrode substrate being attached to a lower end of the container body so as to form a plurality of wells. The container body is made from resin and comprises a plurality of tubular portions whose upper and lower ends are open, each of the tubular portions comprises in an inner cavity a measurement portion tapered toward the lower end and having a measurement hole at the lower end, and further on an inner wall at least two retaining means retaining the measurement portion. The electrode substrate comprises a substrate body, with a plurality of measurement electrodes and a plurality of reference electrodes being disposed on one surface of the substrate body. The container body is attached to the surface of the substrate body on which the measurement electrodes and the reference electrodes are disposed, such that the measurement electrodes are exposed through the measurement holes.