The present invention provides a loudspeaker including an edge formed in such manner that a thickness of a sectional shape in a radial direction increases from an inner peripheral portion toward an outer peripheral portion. Due to this structure, a mechanical impedance of the edge against a diaphragm is decreased and bad influences on a vibration mode of the diaphragm are suppressed, and also, vibration energy is absorbed by a thick portion of the outer peripheral portion, thereby suppressing standing waves of the diaphragm.