To improve contact of a movable contact and a first fixed contact and to improve reliability by providing a contact part made of a deformable dome-shaped metallic plate which has spring performance, having a tip projected to the dome-shaped inner part, capable of being brought into contact with and separated from a fixed contact, and having a plurality of contact points to the fixed contact.

When a pressing force is applied from above by a push button, force is applied in the direction of an arrow, and the upper surface part of a movable contact 1 is deformed into a recessed shape via a cover part 9. The whole lower part of a cylindrical contact part 1b formed on the tip of the movable contact 1 is contacted in annular form to a first fixed contact 8a by a plurality of contacts to make an ON-state between the first fixed contact 8a and a second fixed contact 8b. When the pressing force is released, the cylindrical contact part 1b of the movable contact 1 is separated from the first fixed contact 8a to turn into of OFF-state between the first fixed contact 8a and the second fixed contact 8b.