A medical manipulator includes: an operation member configured to drive so as to operate a treatment tool; a treatment tool side drive shaft configured to rotate about an axis thereof so as to drive the operation member; an operation amount detection member connected to the treatment tool; a treatment tool side detection shaft configured to rotate about an axis thereof in accordance with displacement of the operation amount detection member; a drive unit side drive shaft engaged with the treatment tool side drive shaft; a drive unit side detection shaft engaged with the treatment tool side detection shaft; a shape regulation section configured to regulate a shape of the treatment tool to a predetermined operation state; and a phase setting section configured to set phases in rotational directions of the treatment tool side drive shaft and the treatment tool side detection shaft.