To provide the structure of an instrument capable of enlarging the sound of a sound source and moreover capable of preventing the dust from entering into the housing without increasing the manufacturing cost.

The substrate 16 fixed with the sound source 20 is arranged in the upper housing member 12, in the lower housing member 13, the opening 24 corresponding to the sound source 20 is formed, and the resonator tube 26 for amplifying the sound of the sound source 20 by resonance is provided at the marginal part 24a of the opening 24 integrally with the lower housing member 13.