To provide a connecting means for fitting a catheter easily and positively to a subcutaneoues implanting system.

This tube connecting device is provided with a ring 10 having a principal shaft a wall, at least one inner void extended along the principal shaft inside the wall, and two opposed distal and proximal free ends undeformable in a radial direction. One outer surface of a system 30 is protrusively provided with a stem 20 for fitting catheter 40. A diameter enlarged part is formed at a distal end of the stem 20. A flange protruded inward to fix the catheter 40 between the flange and the protruding part of the stem 20 is formed inside the ring 10. This flange is divided in a plurality of sectors, and a slit is formed between the sectors.