Provided is a medical instrument which has improved operability of an insertion portion and can guide a distal end of the insertion portion to an intended position. The medical instrument includes: an insertion portion (10) which is inserted into a body cavity a rotor (11) which is provided in an outer circumferential surface of the insertion portion (10) and has its rotational axis arranged in a direction along an axis of the insertion portion (10) and a rotary drive unit which rotates the rotor (11) around the rotational axis.
