<p>A vacuum valve is disposed in one side across a base plate. The fixed electrode terminal at the fixed electrode end of the vacuum valve and the moving electrode terminal at the moving electrode end are supported by a pair of insulation supports erected on the base plate. The opposite side of the vacuum valve across the base plate is fitted with an operation mechanism. The operation mechanism is coupled with a contact switching link mechanism connected to the moving electrode by means of a drive means disposed inside the insulation support along the support direction.</p>
