To provide a highly durable ultrasonic transducer by maintaining the excellent bonded state between a metallic planar body and a ceramic piezoelectric body.

The ultrasonic transducer 100 includes the ceramic piezoelectric body 3 for generating a voltage through deformation, and the metallic planar body 1 bonded to the specified surface of the ceramic piezoelectric body 3, the metallic planar body 1 receives ultrasonic waves W, voltage signals result from the ceramic piezoelectric body 3, the ceramic piezoelectric body 3 receives the voltage signals, and the ultrasonic waves W result from the metallic planar body 1. The metallic planar body 1 is bonded to the specified surface f of the ceramic piezoelectric body 3 using the adhesive 2 of a glass transition temperature lower than the lowest using temperature of the ultrasonic transducer 100.