Provided is an initialization method for a manipulator system having a medical instrument that has a joint for bending and a shaft-shaped portion, a driving force transmission unit, a drive unit that supplies a driving force, and a driving force relay unit that can be switched between a driving force relay state and a driving force release state, said manipulator system initialization method being provided with: a joint angle setting step in which a joint for bending and a pair of shaft-shaped portions which are connected by this joint for bending are inserted, in a driving force release state, into a shape regulation member having a shape regulation portion that configures the joint angle of the joint for bending to a prescribed value, and the joint angle is set to a prescribed value a drive unit connection step in which the driving force relay unit is switched to a driving force relay state and an origin setting step in which the state of the joint angle of the joint for bending is mapped to the drive origin of the drive unit after the drive unit connection step has been performed.