PURPOSE: To decrease the load and friction force of ball casters and to move freely a fountain device by placing said device under the water surface, providing the ball casters at the bottom end and further using a float.

CONSTITUTION: A buoyant tank 2 acting as a float is fixed by means of fixtures 3 to a steel pipe frame body 1 in common use as a water feed pipe. Four ball casters 9aW9d are further attached to the bottom end of the body 1. Then the load of the device on the base of a pond is decreased by the buoyancy and therefore the friction force in the stage of moving is small and the device is easily moved with slight horizontal force; moreover the device is kept submerged in water without exposure above the water.