To provide a hydrodynamic force power-generating device which converts energy which a fluid has such as the flow of water or tide to electrical energy, and which can be easily installed, moved, and removed.

The hydrodynamic force power-generating device is constituted by a rotor 10, a bearing 9, gearing equipment 4, a transmission, conduction equipment, a generator, a lead wire, a capacitor, an elevator 8, and a floating deck 1 on which these are mounted. The rotor 10 is integrated with a shock plate 11 (11a) which receives energy the fluid has. Then the floating deck 1 is moored over a water surface. The shock plate 11 (11a) which receives energy the fluid has is continuously inclined with a moderate angle, and is welded on the axial center of the rotor. Then the rotor 10 integrated with the shock plate 11 (11a) which receives energy the fluid has by a welding structure has a hollow structure that both ends on the axial center are shaped like a cone.