A hydraulic power generating device may include a power generating hydraulic turbine having a plurality of first blades projected on an outer peripheral side and a cylindrical plate part which may be coaxially structured with a rotating center axial line of the power generating hydraulic turbine at a position adjacent in an axial direction to the first blades, and an ejection port for ejecting water may be opened both to the first blade and to the cylindrical plate part. Further, hydraulic power generating device may include a power generating hydraulic turbine having a hollow cylindrical body, a first cylindrical radial bearing and a second cylindrical radial bearing. The second radial bearing may be positioned at a second end part of the hollow cylindrical body with a shaft hole of the first radial bearing as the reference.