Floating body for tidal current power generation and power generation method using same

A floating body for tidal current power generation of the present invention comprises: a power generation unit comprising a water wheel and a power generator connected to the water wheel; and a body part provided with tidal current inlet and outlet paths having a cross-sectional area that is gradually reduced from the front and rear surfaces thereof toward the water wheel. According to the present invention, a plurality of floating bodies for tidal current power generation are disposed in parallel so that the longitudinal direction of the tidal current inlet and outlet paths coincides with the direction of the tidal current in a terrain such as a strait with a narrow width. In addition, provided is a power generation method which is a method for adjusting the draft of a floating body for tidal current power generation depending on the flow velocity of the tidal current, thereby smoothly performing power generation even when the flow velocity of the tidal current becomes slower as tidal stand nears.