To provide a floating body structure and a method of manufacturing the same which can suppress its cost low by manufacturing wide floating body structures using an existing building dock.

The floating body structure has cavities 3L, 3R inside, is made up of a pair of split bodies 2L, 2R of a half-split shape formed by dividing at the boundary of a parting plane S, and can float on water. The split bodies 2L, 2R are fabricated so that the parting plane S in the longitudinal direction is formed at the center in the width direction. Shielding parts 4, which prevent water infiltration into the split bodies 2L, 2R by separating the insides from the outsides of the split bodies 2L, 2R, are provided on each of the split bodies 2L, 2R along the parting plane S.