A cylindrical balloon for medical tubes, which is susceptible to bending operations, comprises a low stretchable section formed, by a partial cross-linking treatment, on the balloon along the circumferential direction thereof. A medical tube equipped with a balloon comprises a shaft tube for being inserted into a living body, a cylindrical balloon liquid-tightly connected to the shaft tube at the periphery on the tip thereof, a first lumen which is formed within the shaft tube and which communicates with the interior of the balloon, and at least one second lumen which is formed within the shaft tube and which is opened at the tip of the shaft tube; or comprises a shaft tube which is inserted into a living body, a cylindrical balloon, one end of which is liquid-tightly connected to the shaft tube at the tip thereof, a long tool for medical treatments or for diagnoses, whose tip portion is liquid-tightly connected to the other end of the balloon directly or indirectly, and a lumen which is formed within the shaft tube and communicates with the interior of the balloon so that a liquid can pass through the balloon and which accommodates the long tool for medical- treatments or for diagnoses, wherein the cylindrical balloon is the same as that defined above.