A power storage device comprising: an electrode body that includes a first electrode and a second electrode; a battery case that accommodates the electrode body and includes a first surface where a penetration hole is provided; and a first electrode terminal that penetrates the penetration hole of the battery case and is electrically connected to the first electrode, wherein the first electrode terminal includes a first conductive member in which a first metal occupies a maximum ratio on a mass basis, a second conductive member in which a second metal that is different from the first metal occupies a maximum ratio on a mass basis, the second conductive member having a shaft part disposed in the penetration hole , and a metal joined part where the first conductive member and the second conductive member are joined, the metal joined part includes, at a cross section being perpendicular to the first surface , passing an axial center (C) of the shaft part , and extending in a radial direction of the shaft part , a first region in which the first metal occupies 70 mass% or more and a second region in which the second metal occupies 70 mass% or more, and when a surface passing a border part where the first conductive member and the second conductive member are in contact with each other around the metal joined part is a border surface (B), the first region includes a region (A1) that exists on a side of the first conductive member relative to the border surface (B) and a first protrusion region (P1) that protrudes toward the second conductive member relative to the border surface (B), and the second region includes a region (A2) that exists on a side of the second conductive member relative to the border surface (B) and a second protrusion region (P2) that protrudes toward the first conductive member relative to the border surface (B). an electrode body that includes a first electrode and a second electrode; a battery case that accommodates the electrode body and includes a first surface where a penetration hole is provided; and a first electrode terminal that penetrates the penetration hole of the battery case and is electrically connected to the first electrode, wherein the first electrode terminal includes a first conductive member in which a first metal occupies a maximum ratio on a mass basis, a second conductive member in which a second metal that is different from the first metal occupies a maximum ratio on a mass basis, the second conductive member having a shaft part disposed in the penetration hole , and a metal joined part where the first conductive member and the second conductive member are joined, the metal joined part includes, at a cross section being perpendicular to the first surface , passing an axial center (C) of the shaft part , and extending in a radial direction of the shaft part , a first region in which the first metal occupies 70 mass% or more and a second region in which the second metal occupies 70 mass% or more, and when a surface passing a border part where the first conductive member and the second conductive member are in contact with each other around the metal joined part is a border surface (B), the first region includes a region (A1) that exists on a side of the first conductive member relative to the border surface (B) and a first protrusion region (P1) that protrudes toward the second conductive member relative to the border surface (B), and the second region includes a region (A2) that exists on a side of the second conductive member relative to the border surface (B) and a second protrusion region (P2) that protrudes toward the first conductive member relative to the border surface (B). <EOS>