An electrolytic capacitor (K1-K3) with an open circuit mode mechanism, comprises: a metallic casing (32; 52; 62) for accommodating a capacitor element (31; 51; 61); an upper lid (33; 53; 63) which is mounted on a mouth of the metallic casing; a pair of metallic rivets (35; 54; 65) which are secured to the upper lid; a pair of external connection terminals (39; 55; 70) each of which is connected to one end portion of each of the metallic rivets; and a fixing member (40; 56; 71) which is molded by resin and is formed with a pair of through-holes (41; 57; 72) each for passing the other end portion of each of the metallic rivets therethrough such that the other end of each of the metallic rivets projecting out of the fixing member is connected, by metallic junction, to each of a pair of lead-out lead plates (42; 58; 73) drawn from the capacitor element. In case pressure in the metallic casing rises due to a malfunction of the electrolytic capacitor, the upper lid is deformed by this rise of the pressure, so that the metallic rivets are lifted in a direction away from the capacitor element upon this deformation of the upper lid and thus, the metallic junction between the other end of each of the metallic rivets and each of the lead-out lead plates is cut off, thereby resulting in break of an electric circuit of the electrolytic capacitor.