According to the hand control system (2), the position and posture of a palm (10) are controlled such that the object reference point (P.sub.w) and the hand reference point (P.sub.h) come close to each other and such that the i-th object reference vector (.alpha..sub.wi) and the i-th hand reference vector (.alpha..sub.hi) come close to each other. During the controlling process of the position and posture of the palm, the operation of a specified finger mechanism is controlled such that the bending posture of the specified finger mechanism gradually changes (for example, such that the degree of bending gradually increases). This ensures accurate grasping of an object of an arbitrary shape.