PURPOSE: To give a sufficient stroke to a diaphragm in the axial direction and to reduce a distortion due to nonlinearity of driving force versus displacement at the time of large input by providing an edge made by forming a plate formed into corrugated sectional form into a curved form as a whole.

CONSTITUTION: The speaker edge is made by forming a finely-corrugated edge plate into a curved from as a whole. An edge having such a form is larger in the surface area of edge as compared with conventional corrugated or roll- shaped edges, and the elongation of the diaphragm due to the force in the axial direction becomes larger, and a sufficient axial stroke becomes available. Accordingly, distortion due to nonlinearity of driving force versus displacement at the time of large input can be decreased. As it has a finely-corrugated part, it has a sufficient controlling force to the force perpendicular to the axis of the diaphragm and can oscillate the diaphragm only in axial direction.