Ultrasound endoscope and ultrasound balloon for endoscope

An ultrasound endoscope comprising:

• an ultrasound transmitting and receiving portion that is arranged at a distal end portion of an insertion portion, which is inserted into a subject, and transmits and receives ultrasound;
• a cylindrical balloon closed at a distal end that is arranged to cover the ultrasound transmitting and receiving portion, includes an annular portion at the distal end, and includes a distal end cover portion that closes the annular portion;
• a first concave groove that is arranged at a distal end of the ultrasound transmitting and receiving portion and in which the annular portion is fit to lock the balloon, the first concave groove being formed over an entire circumference of the ultrasound transmitting and receiving portion;
• a distal end face that is provided on the distal end side of the ultrasound transmitting and receiving portion to form the first concave groove and covered with the distal end cover portion;
• and
• at least one convex portion that is in contact with an inner side surface of the distal end cover portion to increase a frictional force between a surface of the distal end cover portion and a finger, provided on the distal end face to lift at least a part of the distal end cover portion, and has a spherical crown shape.