Vacuum circuit breaker

A vacuum circuit breaker comprising:

• a pressure vessel filled with an insulating gas of a predetermined pressure;
• a vacuum interrupter disposed in an internal space of the pressure vessel and having a fixed electrode and a movable electrode in a vacuum tube having a vacuum state;
• a bellows provided to seal a gap between the vacuum tube and the movable electrode;
• a movable rod having one end connected to an end portion of the movable electrode via an insulating link, and capable of penetrating the pressure vessel and reciprocating in an axial direction while maintaining air-tightness;
• a driving rod disposed on the other end of the movable rod in an external space of the pressure vessel and transmitting a driving force of a driving unit to the movable rod;
• and
• a contact pressure spring having one end supported by the movable rod and the other end supported by the driving rod,
• wherein a ratio of self-closing force to a minimum input contact pressure in the vacuum interrupter is set to be a predetermined ratio.