An electric storage device pressure regulating apparatus includes: a case in an internal portion of which is disposed a regulating chamber that communicates with a space in a vessel by an opening portion; a semipermeable membrane that seals the opening portion; a check valve that stops discharging of the gas out of the vessel from inside the regulating chamber when the internal pressure of the regulating chamber is less than or equal to a predetermined value, and that discharges the gas out of the vessel from inside the regulating chamber when the internal pressure of the regulating chamber exceeds the value; and a communicating pipe that communicates between a space inside the regulating chamber and a space inside the vessel and extends from the case to an electric storage device main body.