PURPOSE: To provide the hemostatic valve which surely prevents leaking out of blood and has excellent operability by providing the conical recessed part at the flank of a rear end with a small hole at its center and providing the front flank on the opposite side with a projecting part larger than the small hole at the same center as the center of this small hole and forming plural pieces of slits extending radially from its center.

CONSTITUTION: This hemostatic valve 3 is provided with the recessed part 6 to permit easy insertion of a catheter, etc., on the surface exposed on the rear end side of the introducer and is provided with the small hole 4 of the diameter smaller than the diameter of a guide wire at its center. The surface on the front side on the opposite side thereof is provided with the projecting part 7 larger than the small hole 4 at the same center as the center of the small hole 4. Plural pieces of the slits 5 extending radially in a radial direction from its center are formed. The site of the slit 5 of the hemostatic valve 3 is pushed and opened toward the front side to generate a small clearance when the catheter 22 is inserted from an opening end 20 in the rear part of the introducer. The rubber-like elastic body of the hemostatic valve 3 comes into tight contact with the catheter, thus preventing the leakage of the blood.