PURPOSE: To increase strength of a coupling cone by providing a annular rise piece which faces from an outer circumference of a joint piece of a coupling cone coupled to a diaphragm to the voice col side and collar which extends approximately parallel with the joint piece from the top of the rise piece.

CONSTITUTION: An annular rise piece 7b is solidly provided with facing the side of a voice coil 5 from a joint piece 7a of a coupling cone 7 for connecting the cone 7 to a diaphragm 8, and a collar 7c is provided approximatey parallel with the joint piece 7a from the top of the rise piece 7b. Thus the rise piece 7b reinforces strength of the joint piece 7a, and the collar 7c is increased strength and acts as a receiving part of jigs at the time of assembly of the coil 5 and the cone 7. Although the weight of the cone 7 is light, it can increase strength by means of a shape of its outer circumference, and a speaker unit with high performance and high efficiency can be formed.