A substructure for an offshore wind turbine is disclosed. The substructure for an offshore wind turbine according to the present invention includes: a deck on which the tower of a wind turbine is mounted by the top; a plurality of piles for supporting the deck; and a plurality of pile supports of which one side is supported in the ocean floor and is open to accept sea water using the internal space of the pile supports and of which the other side supports the piles.
