To exclude deviation of a metal terminal, by forming a pair of T-shaped electrode layers on the upper surface of a substrate, and constituting conductive polymer electrically connected with the electrode layer.

A substrate 11 contains 96% alumina having surface roughness of 3-4μm. On the upper surface of the substrate, T-shaped electrode layers 12 composed of nickel are formed from one end of the substrate toward the other end, and from the other end to the one end. Conductive polymer 13 is formed on the upper surface of the substrate 11, to be connected with a pair of the electrode layers 12. The polymer 13 is composition of crystalline polymer and conductive particles, and has PTC characteristics. Side surface electrodes 14 composed of silver are formed on the respective side surfaces of the substrate 11, to be connected with the electrode layers. Thereby movement of the conductive polymer, the electrodes and terminals are reduced, so that mounting by a flow soldering method and repairing work are possible. It is also possible to make heat dispersion constant by forming an outer electrode having a thickness on the lower surface part of the substrate.