A small-sized, light weighted vacuum circuit interrupter comprises a vacuum container (1) confining a vacuum atmosphere of a pressure less than 10- 4 mmHg and a pair of electrodes consisting of a fixed electrode (4) and a movable electrode (5) for making and breaking an electric circuit including either a transformer (22) of a rated surge voltage strength of less than 45 kV or a motor of a rated surge voltage strength of less than 25kV. At least one of the electrodes (4,5) has a contact made of a porous body of a refractory conductive material and an impregnate selected from the group consisting of silver telluride, silver selenide and mixtures thereof impregnated in the porous body in an amount sufficient to give the interrupter a chopping current of not more than 1 A and an arc extinguishing capability of 1 MHz of not more than 27A/µs when measured in a circuit of 6 kV. The interrupter can be connected to the load without a surge absorber for protecting the breaker from a surge voltage generated at the time of interrupting the circuit.