VACUUM VALVE

PROBLEM TO BE SOLVED: To provide a stable and good cut-off performance with a simple electrode structure, by contactably/separatably facing a fixed electrode to a movable electrode in a vacuum container, and providing a slit only in the lower surface of a bottom flat plate of a cup electrode. SOLUTION: A cup electrode 10 of a vacuum valve is formed in a structure where slits 4 provided in a cylindrical portion 2 and a bottom flat plate 3 for an arc causes a magnetic field to occur orthogonally to the arc, Lorenz force acting to self current flowing on the arc with this magnetic field drives the arc occurring between contacts during current cutoff. At this time, the magnetic field orthogonally to the arc that occurs in facing cup electrodes 10 causes the arc to start rotating on contacts. In this case, because no slit 4 exists in the upper surface 6 of the bottom flat plate of the cup electrode, generated magnetic field is reduced. While, because the slit 4 exists in the lower surface 7 of the bottom flat plate of the cup electrode, the lower surface 7 serves as a part of a coil for generating magnetic field to increase a driving force of the arc.