PROBLEM TO BE SOLVED: To provide a living-organ dilator good in trackability, capable of minimizing the propensity of kinking and shortening the time duration of inflation and deflation of a balloon without overextending beyond the outer diameter of a stent for both of balloon's crossing portions. SOLUTION: The living-organ dilator 1 is equipped with a shaft main body 2, a balloon 3 provided at the leading edge of the shaft main body 2 and a stent 4 provided in the folded-back state balloon 3. The crossing portion 33b of the leading end side of the balloon 3 is equipped with a leading end side low gradient portion 331b and a leading end side high gradient portion 332b with a tilt angle &alpha；at 3-10 deg. in the longitudinal axis L of the balloon 3.
