To provide a boat propelling device and a boat controller easy to be fitted at low cost, usable for a long time, and easy to be operated.

Water or seawater is sucked from a through hull 1 provided in the bottom of a boat by pumping by a pump 2, and a ball valve 5 is suitable for a hose or a hose divided by a metal header 4 connected by a pipe 3, or the pipe. A universal boat can be freely operated by a hydraulic force discharged from the through hulls 1 which are arranged in a bow, a stern and a transom by operating the ball valve 5 which has selected a progressing direction.