Abstract: A sound device can be incorporated into a message decoder. The message decoder roughly comprises a decoder body 10, a front shield plate 20, a buzzer 22, an IC substrate 30 and an LCD 32, a back shield plate 40, an RF receiver 50, and a decoder outer lid 60. One surface of the buzzer 22 having a double-coated adhesive tape 24 is stuck on the front surface of the decoder body 10. Hooks 23a, 23b, 23c and 23d of the front shield plate 20 are engaged with the sides of the decoder body 10 so that a sleeve 26 of the front shield plate 20 may be engaged with a cut edge 16 of the decoder body 10, whereby the other surface of the double-coated adhesive tape 24 of the buzzer 22 is stuck on the back surface of the front shield plate 20. In consequence, when the buzzer 22 emits sound, the decoder body 10 and the front shield plate 20 play the role of a vibrating plate 20.