An electric-connector attachment structure of a battery pack for an electric vehicle, comprising: a battery pack for an electric vehicle, including a tray of a box-like shape which accommodates a battery and has an opening on an upper side, and a cover of a box-like shape having an opening on a lower side, the tray and the cover being joined to each other at a horizontal plane; and an electric connector to which an electrical cable is connected, the electrical cable being connected to the battery pack to supply electric power to the battery pack from outside or to supply electric power to the outside from the battery pack, characterized in that an outer peripheral wall (42,52) of one of the tray and the cover includes: an inclined portion (441,551) forming an inclined surface to which the electric connector is attached, the inclined portion (441,551) being disposed at an inner side of the battery pack with respect to a joint surface at which the tray and the cover are joined to each other, and extending over a lower region and an upper region across the horizontal plane passing through the joint surface; and a protruding portion (443,553) disposed between the joint surface and the inclined portion (441,551) so as to bulge from the horizontal plane passing through the joint surface towards the cover or the tray, and that the inclined portion (441,551) is formed so as to be continuous from the protruding portion (443, 553). a battery pack for an electric vehicle, including a tray of a box-like shape which accommodates a battery and has an opening on an upper side, and a cover of a box-like shape having an opening on a lower side, the tray and the cover being joined to each other at a horizontal plane; and an electric connector to which an electrical cable is connected, the electrical cable being connected to the battery pack to supply electric power to the battery pack from outside or to supply electric power to the outside from the battery pack, characterized in that an outer peripheral wall (42,52) of one of the tray and the cover includes: an inclined portion (441,551) forming an inclined surface to which the electric connector is attached, the inclined portion (441,551) being disposed at an inner side of the battery pack with respect to a joint surface at which the tray and the cover are joined to each other, and extending over a lower region and an upper region across the horizontal plane passing through the joint surface; and a protruding portion (443,553) disposed between the joint surface and the inclined portion (441,551) so as to bulge from the horizontal plane passing through the joint surface towards the cover or the tray, and that an inclined portion (441,551) forming an inclined surface to which the electric connector is attached, the inclined portion (441,551) being disposed at an inner side of the battery pack with respect to a joint surface at which the tray and the cover are joined to each other, and extending over a lower region and an upper region across the horizontal plane passing through the joint surface; and a protruding portion (443,553) disposed between the joint surface and the inclined portion (441,551) so as to bulge from the horizontal plane passing through the joint surface towards the cover or the tray, and that the inclined portion (441,551) is formed so as to be continuous from the protruding portion (443, 553).