To provide a high-efficiency semi-drag type cage type water wheel system to solve a problem wherein a system usable for wind power and hydraulic power with easy structure and installation is not found in the same system at present.

This system is used in a completely submerged state in flowing water in the same way as a windmill used in a completely sunk state into a fluid of air. As advantages and features of this system, no influence by driftwood, etc. is received at the time of flooding due to a typhoon and heavy rain, etc. by installing the system at a place deeper than a water surface when utilizing water current energy of a river and an ocean current, etc., the number of the system to be installed is not limited in the same way as wind, only if water flow of a proper depth and an installation place are given, even in the case of flowing water, and the system can be utilized also for the ocean current and a tide of a channel, etc. This system can be expected to be positively utilized in Japan, in particular, since the system is harmless by utilizing natural energy in view of a future global environment.