An ultrasound probe includes an ultrasound transmission/reception portion which transmits and receives ultrasound, a proximal-end-side balloon fixing portion arranged on a more proximal end side than the ultrasound transmission/reception portion and having a stepped shape in which a proximal end side is high, and a balloon fixing tool mounting groove arranged on a more distal end side than the proximal-end-side balloon fixing portion and having a width narrower than a width of the proximal-end-side balloon fixing portion.
