There is provided an ultrasonic endoscope of which a supply/discharge pipe line can be efficiently cleaned with a cleaning brush while the diameter and size of a tip portion of an insertion part to be inserted into a body cavity are reduced. The ultrasonic endoscope includes: an insertion part 20 that includes a tip, a base end, and a longitudinal axis； an ultrasonic transducer 62 that is provided at the tip of the insertion part 20； a locking groove 68 that is a balloon mounting portion which is disposed closer to the base end of the insertion part than the ultrasonic transducer 62 is and on which a balloon 64 wrapping the ultrasonic transducer 62 is detachably mounted； a balloon pipe line 104 that extends in the insertion part 20； a tip-side opening surface 70 of the balloon pipe line 104 that is provided closer to the tip than the locking groove 68 and has components normal to a direction of the longitudinal axis； and a groove portion 74 which is formed toward the tip from the tip-side opening surface 70 as a starting point and of which at least a part overlaps the ultrasonic transducer 62 in the direction of the longitudinal axis.
