Rotary to linear conversion is one of important mechanisms and has been widely used in various mechanical systems. We designed a new mechanism for rotary to linear conversion, which can provide linear output mechanically by using both screws and gears, and will be adequate for the both accurate positioning and high capacity. In this study, the compact mechanism designed for retrofit into mechanical devices was manufactured in order to investigate its fundamental performance. In the positioning accuracy test, the positioning accuracy of this mechanism was superior to that of a feed screw employed a precision ball screw. In the load output test, the load output of this mechanism was larger than that of a precision ball screw under some input torque condition.