A button is provided. A fixture fixes a button body to a support from an opposite side to the button body with the support therebetween. The button body includes a collar, a shaft protruding from the collar and an insert hole for the fixture to be inserted therein. An outer circular wall and an inner circular wall are formed at a tip end of the shaft separately from each other with a gap therebetween. The outer circular wall defines an outer periphery of the shaft and at least one protrusion for fixing the support thereon is formed at an upper surface of the outer circular wall. The inner circular wall defines an inner periphery of the insert hole. The protrusion protrudes relative to an upper surface of the inner circular wall and the gap is recessed relative to the upper surface of the inner circular wall.