A lead terminal is passed through a terminal passage hole of a rubber seal, without imposing an excessive burden such that the characteristics of the capacitor element would be degraded, and while maintaining a state of reliable isolation from the outside air. In an aluminum electrolytic capacitor in which the hole diameter f2 of a lead wire passage hole (52) is smaller than the outside diameter f1 of an outside lead wire (22), the outside lead wire (22) being forcibly passed to the outside through lead wire passage hole (52), a conical guide surface (53) of progressively smaller diameter is formed between a round bar mating hole (51) and the lead wire passage hole (52) within a terminal passage hole (5). A passage guide part (222) of progressively smaller diameter from a lead wire body (221) is integrally furnished at an end of the outside lead wire (22) so as to have a smaller diameter f3 than the hole diameter f2 of the lead wire passage hole (52), forming a conical sloped surface (223) having a predetermined angle on the peripheral surface of the passage guide part (222).