The present invention provides a piezoelectric acoustic device 2 capable of preventing substantial deflection of a first side wall 17 opposite a piezoelectric vibrator 13 due to application of force to an integral cylinder 12 in a direction toward the first side wall 17. According to the invention, a piezoelectric vibrator 13 including a piezoelectric ceramic element is received in a two-part receiving casing 9 formed by fitting a first casing half 10 and a second casing half 11 together. The first casing half 10 includes a first side wall 17 opposite to the piezoelectric vibrator 13 and a first peripheral wall 18 extending from the first side wall 17. A front air chamber 30 is defined between the first side wall 17 and the piezoelectric vibrator 13. A cylinder 12 is integrally formed on the first side wall 17 so as to extend in a direction perpendicular away from the plane of the first side wall 17. The cylinder 12 is offset toward an outer periphery of the first side wall 17 so that a part 32 of the base 31 of the cylinder 12 is aligned with a part of the first peripheral wall 18 of the first casing half. An opening 23 is provided through the first side wall 17 for connecting the front air chamber 30 to a passage 29 defined by the interior of the cylinder 12. The opening 23 is situated such that a center 28 thereof is offset toward a center point 25 of the first side wall 17, and is preferably adjacent to the inner periphery of the cylinder 12. The opening 23 is covered with a damping cloth member 27 joined to an inner surface 26 of the first side wall 17 by means of a solvent which dissolves the synthetic resin from which the front casing half 10 is formed but not the damping cloth member 27.