A jerk-initiated switch includes an insulating housing with an inner bottom wall surface, a plurality of electric contact terminals having contact protrusions disposed in the housing to form a polygon, and an electrically conductive ball rollable on the inner bottom wall surface and having a spherical radius of a dimension that is larger than a length from a polygonal center to a polygonal side, and that is smaller than a diagonal section from the polygonal center to a vertex of the polygon. The topography of a central area of the inner bottom wall surface is configured such that the ball is displaced from an upright position where it rests on the central area to a jerked position where it is out of the central area so as to establish different switching states.