To provide an ultrasonic wave transducer the vibration characteristic of which is not affected through the mount of the ultrasonic wave transducer on an external substance so as to avoid the necessity of resonance and/or impedance matching.

The ultrasonic wave transducer is provided with a head mass, an end mass, a vibration mass and two modified elements elastically deformed, a rigid connection means between the head mass and the end mass is placed and the vibration mass is placed between the head mass and the end mass, the one modified element is placed between the head mass and the vibration mass, the other modified element is placed between the end mass and the vibration mass, at least the one of the modified elements consists of a conversion element generating ultrasonic wave vibration or a conversion element permitting the ultrasonic wave vibration element. The vibration mass can carry out vibration that freely traces the ultrasonic vibration generated by the conversion element or permitted by the conversion element relatively with respect to the head mass and the end mass.