An electric storage device includes an electrode assembly, a case housing the electrode assembly, a plastic member arranged at an outer surface of the case and including a joining surface facing the outer surface of the case, an external terminal supported by the plastic member and electrically connected to the electrode assembly, a sealing member arranged at the outer surface of the case, the sealing member including a joining surface facing the outer surface of the case, and an auxiliary terminal supported by the sealing member, the auxiliary terminal extending from inside to outside the case, being electrically connected to the electrode assembly, and being electrically connected to the external terminal. The plastic member includes a material having a hardness greater than a hardness of the sealing member.