A stern structure of a ship includes a plurality of propellers, a plurality of propeller shafts and a stern structural body. A plurality of propeller shaft tubes is provided correspondingly to the plurality of propellers, and the plurality of propeller shafts connected to the plurality of propellers is inserted into the plurality of propeller shaft tubes. The stern structural body extends backwardly from the stern body, spreads externally with respect to a ship body center line C, and contains portions of the plurality of propeller shafts extending backwardly from the stern body. An inner side of the stern structural body is equivalent to an interior portion of a ship body. The stern structural body supports the plurality of propeller shaft tubes in the interior portion of the ship body.