Clip unit, medical instrument, and attaching method of medical instrument

A medical instrument, comprising:

• a capsule that is formed in a cylindrical shape and has a longitudinal axis;
• an arm member disposed to protrude from the capsule and configured to be rotatable together with the capsule about the longitudinal axis;
• an operation wire connected to the arm member, the operation wire being separatable from the arm member;
• a sheath configured to accommodate the operation wire;
• and
• a link configured to connect the sheath with the capsule, the sheath and the capsule being separatable from each other, the link including:
• an engaging portion including a first surface intersecting with the longitudinal axis;
• and
• an engaged portion configured to protrude in an intersection direction with respect to the longitudinal axis, the engaged portion being movable to an opposite position opposite to the first surface and a position spaced away from the first surface in the intersection direction in spite of a relative position of the capsule with respect to the sheath in a circumferential direction about the longitudinal axis, and the engaged portion being configured to restrict a separation of the capsule with respect to the sheath when the engaged portion is disposed at the opposite position to contact the first surface,
• wherein:
• the capsule is rotatable about the longitudinal axis in response to a rotational force about the longitudinal axis from the sheath when the engaged portion is disposed at the opposite position,
• the arm member, the capsule, and the sheath are configured to rotate about the longitudinal axis in an interlocking manner with respect to the operation wire when the engaged portion is disposed at the opposite position, and
• the operation wire and the arm member are relatively rotatable with respect to each other.