PURPOSE: To include the valve closing function in an opening device itself by adding a bar-shaped body at the tip with a cutting edge, and providing the second bar-shaped body behind it.

CONSTITUTION: A device is constituted of the first bar-shaped body 10, the second bar-shaped body 20, a connecting member 30 connecting the first bar- shaped body 10 and the second bar-shaped body 20, and a flexible wire 40 extended from the rear end of the second bar-shaped body 20. When this device is pulled back after it is inserted into a blood vessel, a tongue 51 is stuck and pulled on the surface of the second bar-shaped body 20, a valve is closed immediately after the second bar-shaped body 20 passes the valve, then the closed tongue 51 is opened by the cutting edge 14 of the first bar-shaped body 10. The tongue 51 of the venous valve can be simply opened without requiring the injection of a physiological salt solution.