To make a piezoelectric buzzer compact, and moreover to reduce power consumption while obtaining high sound pressure as an alarm buzzer, in consideration of the present situation where a mounting space is limited and there is constraint in power consumption but large sound pressure is required when the piezoelectric buzzer is used as a sound alarm unit necessary for burglar prevention of a car or the like.

The piezoelectric buzzer is formed by: using a plastic film 4 with a projecting and recessed part formed thereon and the projecting and recessed part of the plastic film 4 to form an air chamber 5 between a diaphragm and the plastic film 4 and piling up two sheets of fixedly arranged vibrator single body 1 of which the flat parts are reversed so as to face each other; further fixing the rims of the plastic films 4 via a fixing ring 8 so that a central air chamber 9 is formed between the vibrator single bodies 1; connecting lead wires to the two sheets of vibrator single bodies 1 to connect them to a driving source; and fixedly bonding either of the plastic film projecting parts of these two sheets of vibrator single bodies 1 to the bottom part inside the case with a double-sided adhesive tape or the like.