PROBLEM TO BE SOLVED: To provide a medical instrument that allows a sub-tube for inserting an operation wire to be fixed in a tubular body without being detached.SOLUTION: A long tubular body 10 includes: a wire reinforcing layer 30 that is formed by winding a reinforcing wire 32 around a main lumen 20 multiple resin sub-tubes 40 that are arranged opposite to the outside of the wire reinforcing layer 30 and each of which defines a sub-lumen having a diameter smaller than that of the main lumen 20 and a resin outer layer 50 that contains the wire reinforcing layer 30 and the sub-tubes 40. An operation wire 60 is inserted into the sub-lumen and has a tip connected to a distal portion DE of the tubular body 10. An operation unit bends the distal portion DE of the tubular body 10 by applying a traction operation to the operation wire 60. The facing sub-tubes 40 in a catheter 100 meander in a circumferential direction of the main lumen 20 in a manner corresponding to each other.
