This paper reports the development and preliminary experiments of a robotic system designed to perform needle manipulation tasks in medical applications. A hybrid type manipulator is designed to enlarge the workspace without loss of position accuracy. In this paper, we initially analyze the workspace and step resolution of the robotic system in the operational space. Then, we perform trajectory tracking experiment to verify that the developed robotic system could be employed to attenuate an unpredictable tremor of human operators and enhance position accuracy in neurosurgery or ophthalmic surgery, etc. It is shown through experimentation that the robothuman cooperation mode is effective for micro-manipulation tasks.