Electric storage device

An electric storage device is provided having a structure that can reliably produce the sealing effect between a case and a sealing member. The electric storage device of the present invention includes an electrode assembly (4); a case (1) that includes a defining wall and houses the electrode assembly (4); a sealing member (11) that is arranged on the defining wall; and a conductive member (12) that is electrically connected to the electrode assembly (4), the conductive member (12) being supported by the sealing member (11), wherein at least a portion of the defining wall where the sealing member (11) is arranged is made of an aluminum-based metallic material; and the sealing member (11) is made of a material that is softer than the material for the at least a portion of the defining wall where the sealing member (11) is arranged.