A piezo-electric speaker capable of easily ensuring a uniform broad-band
sound pressure and reproducing a large acoustic signal has a
piezo-electric member (10) to generate vibration in accordance with an
applied electric signal. A piezo-electric vibration plate (15) is adhered
to the piezo-electric member (10). The piezo-electric vibration plate
(15) converts the vibration to sound. The thickness of the piezo-electric
vibration plate (15) is formed so as to be different in accordance with
the distance from the vibration center of the piezo-electric member (10).