The present paper shows the three-dimensional correction factors for the virtual inertia coefficient and the correction for the rotatory inertia of the virtual added mass of water for horizontal vibration of a ship, including higher modes. Special consideration is given to the three-dimensional correction factors obtained from the theoretical study on the three-dimensional calculation of the virtual mass of water on a half-immersed circuler cylinder of finite length which vibrates on water. In calculating the kinetic energies for the horizontal vibration of the ship and the entrained water, the rotatory energy of the hull and the corresponding virtual rotatory energy of the water are taken into account. In addition the experimental determination of the virtual mass has been carried out on a wooden model of a tanker and the theoretical results are confirmed.