The ultrasonic endoscope includes: an insertion part that includes a tip, a base end, and a longitudinal axis； an ultrasonic transducer that is provided at the tip of the insertion part； a locking groove that is a balloon mounting portion which is disposed closer to the base end of the insertion part than the ultrasonic transducer is and on which a balloon wrapping the ultrasonic transducer is detachably mounted； a balloon pipe line that extends in the insertion part； a tip-side opening surface of the balloon pipe line that is provided closer to the tip than the locking groove and has components normal to a direction of the longitudinal axis； and a groove portion which is formed toward the tip from the tip-side opening surface as a starting point and of which at least a part overlaps the ultrasonic transducer in the direction of the longitudinal axis.
