An auxiliary apparatus for MIS including an in vivo device and an in vitro device to stretch a surgery target is provided. The in vitro device comprises an in vitro magnet field-generating element. The in vivo device comprises an in vivo magnet-anchoring element to the surgery target. The in vivo magnet moves and/or rotates according to the direction change of the external magnetic field, which is generated by the in vitro magnet field-generating element, and thereby the surgery target can move in a controlled speed and/or rotate in a controlled angle according to the direction change of the external magnetic field. A method to control the auxiliary apparatus is also provided.
