An electrochemical device includes an electrode assembly in which a length direction, a thickness direction and a width direction are defined, and a packing member including a first packing film and a second packing film for packing the electrode assembly. The electrochemical device includes a bonded portion formed by bonding an edge of the first packing film with an edge of the second packing film. The bonded portion is configured to be bendable around an axis of the width direction, in a region in the length direction.