A switchgear having interrupters wherein at least two moving contacts are capable of being open and close with respect to respective fixed contacts. The switchgear comprises a non-earthed metal vacuum chamber enclosing the interrupters therein, a connection conductor for connecting the moving contacts, an operating rod connected to the connecting conductor by means of an insulator and protruding from the non-earthed metal vacuum chamber, a sealing means for sealing the protrusion of the operating rod at the non-earthed metal vacuum chamber, circuit terminals protruding from the non-earthed vacuum chamber, an earth layer surrounding an outer periphery of the insulating mold, and a potential control means. The control means for controlling the potential of the non-earthed metal vacuum chamber is connected between the circuit terminals and is connected to the non-earthed metal vacuum chamber at the intermediate point of the potential control means.