Disclosed herein is a method of controlling a robot hand similar to a hand of a human being such that the robot hand naturally and safely grasps an object. The robot hand, including fingers and a palm, is capable of naturally and safely grasping an object, by the tip of each finger performing impedance control while following the optimal path on a Cartesian coordinate system, although the robot hand cannot reach a position ideal to grasp the object due to sensor errors or shape information of the object to be grasped is not correctly recognized. Also, the robot hand is capable of stably grasping the object even when moving or manipulating the object.