A movable contact positioned in a sealed case is moved together with a movable contact spring provided with an armature by a magnetic shunt body which is moved outside the sealed case. The movement of the movable contact (movement of the movable contact spring) due to the movement of the magnetic shunt body is based on the change of the magnetically attracting force of a magnet with respect to the armature through a pair of yokes. The movable contact spring is provided with a bent portion which is bent in spaced-apart relation to the armature, the bent portion being provided between a fulcrum portion at a time when the movable contact spring moves and a portion where the armature is provided.