PURPOSE: To form the axial magnetic field when an arc occurs and suppress the diffusion of this arc by fitting an electrode bar at the center of the rear face of a main electrode via a superconductive member.

CONSTITUTION: An electrode bar 1 is fitted to the center of the rear face of a main electrode 2 via a superconductive member 5. Since the superconductive member 5 maintains the superconductive state when the load current flows and the current resistance becomes zero, all the current flows through this superconductive member 5, and heating due to the Joule's heat is prevented. When the short circuit current is cut off, the superconductive member 5 is converted into the ordinary conductive state, thus the short circuit current is dividedly fed to the superconductive member 5 converted to the ordinary conductive state and a circular arc-shaped coil section 2C based on their resistance ratio. The excessive heating and temperature rise due to the Joule's heat of the load current can be thereby prevented without adding a cooling device or the like, and the residual magnetic field after the zero point of the short circuit current can be reduced, thus a vacuum breaker with high reliability can be obtained.