Demands for human-robot collaboration in production line has increased and the problem of safety in robot becomes more and more important. This paper presents a manipulator with counterbalancing mechanism to secure safety of a human worker in human-robot collaboration environment by reducing a needed power to drive a manipulator. A counterbalancing torque to cancel out a gravitational torque was generated by a restoring force of spring. Also a control algorithm to minimize the effect of spring on tracking performance was proposed. Experimental results were suggested to verify the performance of the proposed method.