[en] This report presents a vector formulation of manipulator kinematics which is different from the homogeneous co-ordinate transformation method now widely used to describe the kinematic relationships between links in a robot manipulator. The fundamental concept of the present description is to express the motions of individual links as those of spatial vectors in a fixed reference co-ordinate system and to obtain a resultant vector using rotation operators. With this idea applied to a six-link manipulator, the kinematic equations were obtained in the completely same form as those derived by the conventional co-ordinate transformation. The advantages of this method are : 1) derivation process is easy to understand intuitively. 2) calculation is much simpler than that by co-ordinate transformation. (author)