To provide a harbor structure which is simple, has a smaller number of driving piles by reducing a lifting force applied to the entire rear surface of a floor slab, and can be constructed at low cost.

The harbor structure 20 is a pile-type or a jacket-type structure having the floor slab 22 held above a water surface, and constructed so as to reduce a lifting force F applied to the rear surface of the floor slab thereof. The harbor structure has an impervious wall 30 arranged therein so as to proportionally dividing the rear surface of the floor slab in a downward direction at least in the water.