An energy storage device (10) includes: an electrode assembly (400) which includes a positive electrode plate (410) and a negative electrode plate (420), wherein the positive electrode plate (410) includes: a positive electrode substrate (411) which is electrically conductive; a positive electrode composite layer (414) which is formed on the positive electrode substrate (411), and an insulating layer (415), at least a part of the insulating layer being continuously formed on the positive electrode substrate (411) and an edge portion (414a) which is a portion including an edge of the positive electrode composite layer (414), and wherein an uneven portion (415a) is formed in the insulating layer (415) above the edge portion (414a) of the positive electrode composite layer (414).