The invention relates to a sheath device for inserting a catheter into a patients body, comprising a first sheath (10, 11, 13, 21, 21, 21", 41, 43, 43) having a proximal end and a distal end, wherein when used as intended the distal end of the first sheath is provided for arrangement in the patients body and the proximal end of the first sheath is provided for arrangement outside the patients body, and wherein the first sheath comprises a tubular section (11, 21, 21, 21", 41) and a sheath housing (13, 43, 43), which is disposed at the proximal end of the section and comprises a receiving channel (46) for a strand-shaped body (20, 20", 20", 32, 66). The invention solves the problem of reliably fixing a second sheath or a catheter with respect to the first sheath by providing a clamping element (54, 54, 55, 56, 56, 57, 57) on the receiving channel (46) for fixing a strand-shaped body in the receiving channel by way of clamping.
