The pressure gauge is double bellows structure that is the two bellows are installed on the both sides of the symmetrical position of “工”shaped brackets. On the top and bottom of “工”shaped brackets are movable end and fixed end which connected by the spring; Two bellows are in parallel state and connect with high voltage connectors by pipe respectively. Gear transmission part is mounted on the fixed end of racket directly and connect with movable end by bar. The dial is fixed to the gear bodies directly.