Provided is an electricity storage device capable of suppressing the amount of heat generated when a positive electrode and a negative electrode short as a result of thermal shrinkage of a separator. This electricity storage device includes a positive electrode (21), a first separator (23), a second separator (24), and a negative electrode (22). The positive electrode has a positive electrode metal foil (21a) and a positive electrode active material layer (21b). A positive electrode uncoated section (21d) is formed in a first end section (21c) of the positive electrode. The positive electrode active material layer extends as far as a second end section (21e). The negative electrode has a negative electrode metal foil (22a) and a negative electrode active material layer (22b). A negative electrode uncoated section (22d) is formed in a third end section (22c) of the negative electrode. The negative electrode active material layer extends as far as a fourth end section (22e). The first separator and the second separator each have a strong connection section (81) and a weak connection section (82). The strong connection sections are positioned at a site in the vicinity of the first end section and extend along the first end section. The weak connection sections are positioned at a site in the vicinity of the second end section and extend along the second end section.