Abstract: Provided are a gait trainer which provides exercise prescription and an exercise prescription system using the gait trainer. The gait trainer comprises a display, pedals on which user's feet are placed, a control unit which receives physical information about the physical condition of the user while the pedals are moving, defines an optimal exercise prescription based on the physical information, and provides the defined exercise prescription to the display. The control unit accesses a server belonging to a health-related organization through a predetermined network, and defines the exercise prescription with the aid of the health expertise received from the server. Since the exercise prescription suitable for the user is provided, exercise efficiency is maximized and possible dangerous health situations can be prevented.