A balloon catheter comprises a shaft 2, a ball-shaped balloon 1 twisted in the form of a screw and mounted on the head of the shaft 2, and a two-way stop cock 5 connected through connection tube 4 with hub 3 on the proximal end of the shaft 2. Injection opening 6 for physiological saline is arranged on the proximal end of the two-way stopcock 5 in order to inflate the balloon. The balloon catheter in the present invention, of which the balloon is of a small diameter during deflation and for which a thinner sheath introducer can be used, can readily occlude a blood vessel.