The present invention relates to a storage tank for a ship. The present invention is arranged in a vertical direction with respect to a hull of a ship to store a liquid cargo such as an LNG in a low-temperature and high-pressure state. The storage tank comprises a cylindrical cylinder unit where a pair of cylinders are overlapped each other; and a partition bilateral-symmetrically dividing an overlapped portion of the cylinder unit with respect to a longitudinal midline of the hull.
