In a temperature adjusting structure for an electric power storage device as well as in a temperature adjusting method for an electric power storage device, a temperature adjusting air that exchanges heat with a case in which an electric power generation element is housed is guided in a longitudinal direction of a circulation path. Then, a vortex flow that swirls with the longitudinal direction being a rotational axis is generated in the air that flows through the circulation path, and the vortex flow is brought into contact with a lateral surface of the case.