This paper describes the development of a needle insertion manipulator for stereotactic neurosurgery. This robot fulfils the requirements of having both a safe mechanical design and the capacity for being sterilized. Many kinds of robots are examined in neurosurgery. Their purpose is the precise positioning of surgical instruments such as biopsy needles, electrodes etc. Some are already available commercially and have been proven useful in the operating theatre. However, their clinical application is limited by specific problems including cost, safety, positioning requirements, maintenance requirements. The main problems have been with the safety of the mechanical design and difficulties with sterilization and disinfecting pre-and post operatively. The manipulator described in this report achieves mechanical safety and has the capacity for cover-sheet-free sterilization. The manipulator has three major components: the main mechanical component (with 6 degrees of freedom), the torque transmission component, and the electric motor, which cannot be sterilized. The electrical parts are detachable. Using this mechanism, we can clearly separate the surgical area from the mechatronics components. In this paper, the basic design and the prototype development and testing are described.