A spherical movable contact is housed in housing portions of a first case and a second case so as to be able to roll, and is to come into or go out of contact with a first fixed contact and a second fixed contact. The first case and the second case are fixed to each other so as to form an integral body in such a manner that the first fixed contact and the second fixed contact are opposed to each other. At least one of the first fixed contact and the second fixed contact is divided. The movable contact is disposed so as to roll while bridging the first fixed contact and the second fixed contact. Contact portions where the movable contact is to contact the first fixed contact and the second fixed contact assume arc shapes, respectively.