To reduce a low resonance frequency at a low cost without losing the reliability in the speaker unit where an outer circumference of a diaphragm is fixed to a mount face of a frame via an edge and a base of the diaphragm or a bobbin is fixed to the frame via a damper.

A mount face 28a has been adhered over the entire outer circumferential face of an edge 29 conventionally. A notch 28b is provided to the mount face 28a and the notch 28b is supported by a bridge structure of a ground paper sheet 30. Thus, an outer diameter D2 of a damper 31 is selected larger than an outer diameter D1 of the edge 29 so as to reduce a minimum resonance frequency. The notch 28b has only to be formed to the frame 28 and the notch is produced by a conventional punch process, and after a frame 28 and a yoke 23 are adhered, the damper 31 is adhered and the reliability of the adhered part is not lost.