The quality of sound genrated is improved and the appearance is also improved. A loudspeaker diaphragm (10) has at its slant portion a projection shown representatively by an edge (4) and a recess shown representatively by an edge (5). The projection is formed radially from the center and curved toward the edge in the circumferential direction. Therefore when the loudspeaker diaphragm (10) vibrates with a large amplitude and the center moves toward the bottom, a rotational force is exerted on the air tending to gather at the center and thereby the press against the center is mitigated. The loudspeaker diaphragm (10) has a three-dimensional structure similar to a screw propeller and is reinforced as a whole to suppress split vibration. The loudspeaker diaphragm (10) is produced by injection molding largely of polypropylene. A variety of colors can be easily given to it when produced. The color and its peculiar structure like a screw propeller impart strong impression.
