The present invention provides a composite piezoelectric transducer having a piezoelectric ceramic, an organic polymer, and an electrode group formed only on surfaces of the piezoelectric ceramic. The groove is formed, having a depth 50% to 90% of the thickness of the piezoelectric ceramic. A ratio, between a width of a non-diced area formed by forming the groove on the piezoelectric ceramic and the depth of the groove is 0.2 to 0.7. An organic polymer is filled in the groove formed in the piezoelectric ceramic in a state including bubbles. The electrode group comprises a first electrode and a second electrode, the first electrode being formed on a first surface of the piezoelectric ceramic, and the second electrode being formed on a second surface of the piezoelectric ceramic, a side surface thereof, or on the second surface, the side surface and the first surface, the second surface being opposite to the first surface in the direction of the thickness of the piezoelectric ceramic. Thus, it has a high coefficient of electromechanical coupling (kt) in the direction of the thickness, and a reduced acoustic impedance, and preferably used especially in an ultrasonic cleaning equipment.