Medical manipulator and method of initializing medical manipulator

A medical manipulator comprises: an insertion portion; an arm portion; a light emitting unit which emits a beam of laser light (L) having an optical axis that is parallel with an arm axis; an imaging unit which images a trajectory of a light image of the beam of laser light (L); a rotation drive motor which rotates the arm portion about a reference axis; and an initialization control unit which controls initialization for aligning the arm portions along the reference axis. The initialization control unit includes: a trajectory acquiring control unit which acquires a trajectory of the beam of laser light (L) by controlling the light emitting unit, rotation drive motor and imaging unit; a convergence test unit which calculates the diameter of the trajectory and tests convergence of the diameter of the trajectory; a drive amount revision unit which determines an amount of drive of a first joint such that the diameter of the trajectory becomes smaller and drives the first joint; and a convergence operation contro