Provided is a dome-shaped spring for placing on a substrate having stationary contacts, and a circumferential edge of the dome-shaped spring is continuously in contact with the stationary contacts. At least a part of a neutral plane has a shape defined by an even function of at least eighth-order. Angle α of the neutral plane of the dome-shaped spring to the substrate at a second inflection point that exists at a second-positioned inflection point from the circumferential edge, angle β of the neutral plane to the substrate at a first inflection point, and angle γ of the neutral plane at the circumferential edge of the dome-shaped spring to the substrate satisfy following inequalities of α β and β γ.