PURPOSE: To provide an electrolytic capacitor, wherein the initial characteristic values are very small and the capacitance is very large at the low impedance and the low equivalent series-resistance in the specified frequency region by forming a capacitor part at the approximately central part of a metallic substrate, providing an input/output external cathode terminals at the surface of the capacitor, and providing an input/output external anode terminals at both ends of the substrate.

CONSTITUTION: On the surface of a metallic substrate 1, on which a dielectric oxide film is formed, a capacitor part 3, wherein a functional polymer film having the conductivity is formed, is provided. The capacitor part 3 is formed at the approximately central part of the metallic substrate 1. External input/ output terminals 7-1 and 7-2 are provided at a cathode attaching plate 7 in bonding with the cathode lead-out terminals on the surface of the capacitor. Input/output anode terminals 4 and 5 are provided at both ends 1-1 and 1-2 of the metallic substrate 1. Therefore, in the capacitor, four-terminals structure is provided, the impedance and the equivalent series- resistance value in the high-frequency region of 100kHz-1MHz is 10mΩ or less, the initial characteristic values are very low and the capacitance is large.