Indicator for pressure container

An indicator for pressure container, comprising:

• a case mountable in a gas filling passage of a pressure container;
• a valve element which is urged by a spring force toward one side of the case connectable to the pressure container, the valve element being movable in the case to a position balanced with gas pressure in the pressure container;
• a seal member for ensuring gas tightness between the valve element and the case;
• and
• an indicating member slidable relative to the case between a position protruding outside the case and a position not protruding;
• wherein the seal member is arranged on the valve element so that the seal member is in contact with the case to ensure gas tightness when the valve element is in a first balanced position while a gas pressure in the pressure container is a predetermined value or higher and the seal member is out of contact with the case not to ensure gas tightness when the valve element is in a second balanced position while the gas pressure is less than the predetermined value, the spring force and a force of the gas pressure are equally balanced at the first and second balanced positions.