Outer sheath

The utility model discloses an outer sheath which is provided with a detachable sheath body and a detachable sheath tail, so that after a catheter is placed into a bladder, the outer sheath can be detached and stripped from the catheter, and the outer sheath can be taken out under the condition that the normal use of the catheter is not influenced. Comprising a sheath body and a sheath tail, the sheath body and the sheath tail are both of a hollow shell structure and are communicated, a first opening allowing a catheter to penetrate is formed in the sheath body, and the catheter can penetrate into the first opening, enter the sheath body and penetrate out of the end of the sheath body; the sheath body comprises a first buckling part and a second buckling part which are detachably connected, and the first buckling part and the second buckling part can be separated or buckled in the direction perpendicular to the axial direction of the sheath body; the first buckling part and the second buckling part each compr