To provide a drive unit that drives a moving part with a relatively simple constitution and performs positioning with high accuracy.

The drive unit comprises a momentum generating device that is installed to the moving part attached movably to a fixing part and moves the moving part by generating momentum, and a stop device that is installed to the moving part and stops the moving part that is liable to move. A driving force for moving the moving part is obtained by generating the momentum by the momentum generating device, the moving direction of the moving part is controlled by properly operating the stop device, and the moving part can be stopped at an arbitrary position, thus driving the moving part and facilitating the positioning with the relatively simple constitution.