An ultrasonic endoscope having a small size and a slight temperature rise of an insertion part even when the transmission output of an ultrasonic transducer part is increased or an imaging device is attached thereto. The ultrasonic endoscope includes: an ultrasonic transducer part having plural ultrasonic transducers for transmitting and receiving ultrasonic waves; a flexing part for flexibly supporting the ultrasonic transducer part; a coupling part for coupling the flexing part to an operation part; a covering material for covering at least the flexing part and the coupling part; and a heat-conducting member provided inside of the covering material and coupled to the ultrasonic transducer part, for transferring heat generated in the ultrasonic transducer part to the operation part.