HanDo relieves the financial distress arising from the frequent replacement of an entire prosthesis. It also aids the daily life of child amputees and satisfies their learning needs at school so that they can grow happily and healthily.By using a structural design, we have improved the replacement problem of below-elbow prostheses. As we only need to replace the socket, the frequency of replacing an entire prosthesis decreases and its lifespan is extended.