An aluminum electrolytic capacitor comprising: a capacitor element formed by winding, via a separator, an anode foil and a cathode foil both having lead terminals attached thereto; an armor case having a bottomed cylindrical shape in which the capacitor element is housed together with a predetermined electrolytic substance; and a rubber seal having a terminal passage hole for the lead terminals drilled therein and mounted on an opening section of the armor case, the lead terminal including a tab terminal having a flat section and a round bar section and an outside lead wire having a lead-free tin plated layer on a surface and welded to an end of the round bar section, the terminal passage hole of the rubber seal including a round bar mating hole, in which the round bar section of the tab terminal is fit, and a lead wire passage hole coaxial with the round bar mating hole and smaller in diameter than the round bar mating hole, the outside lead wire being inserted through the lead wire passage hole, and a hole diameter of the lead wire passage hole being smaller than an outer diameter of the outside lead wire, the outside lead wire being forcibly inserted through the lead wire passage hole to be drawn out to the outside of the armor case, and a welded section of the round bar section and the outside lead wire being shut off from an outside air, wherein a conical guide surface gradually reduced in diameter is formed between the round bar mating hole and the lead wire passage hole in the terminal passage hole, the outside lead wire includes a lead wire body larger in diameter than the hole diameter of the lead wire passage hole and a passage guide part integrally connected to a distal end portion of the lead wire body, the passage guide part is formed to be gradually reduced in diameter from the lead wire body to be smaller in diameter than the hole diameter of the lead wire passage hole, and in the passage guide part, a conical sloped surface having a predetermined inclination angle is formed, and when an inclination angle of the guide surface with respect to an imaginary plane X orthogonal to an axis Y passing the terminal passage hole is represented as θa and the inclination angle of the sloped surface is represented as θb, then θa < θb. a capacitor element formed by winding, via a separator, an anode foil and a cathode foil both having lead terminals attached thereto; an armor case having a bottomed cylindrical shape in which the capacitor element is housed together with a predetermined electrolytic substance; and a rubber seal having a terminal passage hole for the lead terminals drilled therein and mounted on an opening section of the armor case, the lead terminal including a tab terminal having a flat section and a round bar section and an outside lead wire having a lead-free tin plated layer on a surface and welded to an end of the round bar section, the terminal passage hole of the rubber seal including a round bar mating hole, in which the round bar section of the tab terminal is fit, and a lead wire passage hole coaxial with the round bar mating hole and smaller in diameter than the round bar mating hole, the outside lead wire being inserted through the lead wire passage hole, and a hole diameter of the lead wire passage hole being smaller than an outer diameter of the outside lead wire, the outside lead wire being forcibly inserted through the lead wire passage hole to be drawn out to the outside of the armor case, and a welded section of the round bar section and the outside lead wire being shut off from an outside air, wherein a conical guide surface gradually reduced in diameter is formed between the round bar mating hole and the lead wire passage hole in the terminal passage hole, the outside lead wire includes a lead wire body larger in diameter than the hole diameter of the lead wire passage hole and a passage guide part integrally connected to a distal end portion of the lead wire body, the passage guide part is formed to be gradually reduced in diameter from the lead wire body to be smaller in diameter than the hole diameter of the lead wire passage hole, and in the passage guide part, a conical sloped surface having a predetermined inclination angle is formed, and when an inclination angle of the guide surface with respect to an imaginary plane X orthogonal to an axis Y passing the terminal passage hole is represented as θa and the inclination angle of the sloped surface is represented as θb, then θa < θb.