This ultrasonic endoscope includes: an ultrasonic transducer (100)； balloon grooves (101, 104)； contacting portions that constitute the bottoms of the balloon grooves (101, 104) and contact balloon bands (113, 114)； first wall portions (102, 105) which have first wall surfaces (102, 105) constituting the ultrasonic transducer side surfaces of the balloon grooves (101, 104) and which are configured so that a first distance, which is the distance from the center of a cross section orthogonal to the direction in which the inserting portion extends to the outer periphery of the first wall surfaces, is greater than a second distance, which is the distance from the center of the cross section to the outer periphery of the contacting portions； and second wall portions (103, 106) which have second wall surfaces (103, 106) which constitute the surfaces of the opposite sides of the balloon grooves (101, 104) from the first wall surfaces (102, 105) and which are configured so that a third distance, which is the distance from the center of the cross section to the outer periphery of the second wall surfaces (103, 106), is greater than the second distance and so as to have a notched portion that defines a surface that is located at a distance from the center of the cross section greater than the second distance but smaller than the distance for the direction for which the third distance is largest.La présente invention concerne un endoscope à ultrasons comprenant : un transducteur ultrasonore (100) ； des rainures de ballonnet (101, 104) ； des parties de contact qui constituent les fonds des rainures de ballonnet (101, 104) et mettent en contact les bandes de ballonnets (113, 114) ； des premières parties de paroi (102, 105) qui présentent des premières surfaces de paroi (102, 105) constituant les surfaces latérales de transducteur ultrasonore des rainures de ballonnet (101, 104) et qui sont conçues de sorte qu'une première distance, qui est la distance depuis le centre d'une sect
