A speaker includes an elongated diaphragm and a coupling member including forward and rearward segments, wherein at least two protrusions are provided at the rear side of the diaphragm along the major axis direction, the forward segment is engagingly disposed between the opposing end faces of two adjacent protrusions and also between the two portions of a rib of the diaphragm opposing each other in the minor axis direction, and wherein the outer circumferential surface of the voice coil bobbin is connected to the inner circumferential surface of the rearward segment, whereby the voice coil bobbin having a diameter larger than the dimension of the diaphragm measured along the minor axis direction can be successfully attached to the diaphragm. In the speaker described above, the diameter of the voice coil bobbin can be increased without decreasing the width of a surround thus enabling the withstanding of higher power input.