A vacuum type circuit breaker which has an operating lever (31) connected at one end thereof to the movable electrode (102) of a vacuum switch tube (1) and at the other end to a closing spring (55) through an energy storage link mechanism (54). The operating lever (31) functions to drive the movable electrode (102). The energy storage link mechanism (54) is provided with an energy storage crank (52) pivotally supported on a shaft (2051). The force which the energy storage link mechanism (54) applies to the operating lever (31) is set such that it is less than a force on the operating lever (31) which is produced by the difference between the internal pressure of the vacuum switch tube (1) and atmospheric pressure. This arrangement makes it possible, upon occurrence of vacuum loss, to detect the vacuum shortage, whereupon the closing of the switch is prevented to thereby avoid an accident due to vacuum degradation.