An energy storage device includes: a case; an electrode terminal having a terminal body, a shaft, and a step disposed at the root of the shaft; and an upper insulating member disposed between the terminal body and the case. The upper insulating member has a terminal support part abutting on a terminal bottom surface of the step and a wall part facing the end face of the terminal body. On one of the terminal body and the upper insulating member, a convex part projecting toward the other of the terminal body and the upper insulating member is formed at a position between the step and the wall part. A gap is formed between the terminal body and the upper insulating member on the side of the convex part.