Unmanned Underwater Vehicles are essential systems in military fields, industrial areas, hazardous environment, scientific researches and rescue fields. In unmanned underwater vehicles, remotely operated vehicles are widely used in many kinds of fields because it is easy to operate and to supply electric power. It is difficult to design remotely operated vehicles owing to water pressure in underwater, electrical danger and complex dynamics of controls. This thesis deals with a process of development of a general class remotely operated vehicle. It is designed to resist external pressure in underwater to be operated in stable electrical provision. And it has functions to control depth and heading automatically. Designs are done in mechanical parts and electrical parts. Finally, performance is tested at a small pool.