PROBLEM TO BE SOLVED: To provide a catheter device which permits the action of a prescribed tensile force or greater on a slide operation line due to an excessive manual operation to be prevented.SOLUTION: A tensile force release mechanism 100 releases a prescribed tensile force or greater acting on the slide operation line 40 due to a relative movement by a rotation operation member 70. Consequently, a prescribed tensile force or greater will never act on the slide operation line 40 along which a sheath 16 is bent. Consequently, the catheter device can prevent a prescribed tensile force or greater from acting on the slide operation line 40 due to an excessive manual operation, fracturing the slide operation line 40 and disabling the operation. Furthermore, the device can prevent the distal end of the sheath 16 inserted into a thin blood vessel from being forcibly bent and damaging a thin blood vessel.
