To fully ensure safety even in a case where a tsunami or the like hits a ship and capsized, by overcoming such the problem that, although conventionally it is possible to reduce the capsizing possibility of a ship, but once the ship is capsized or immersed in water against the buoyancy, it is hard to cope with the situation and to ensure safety.

This ship includes: a watertight standby chamber 0101 generating buoyancy for preventing the ship from sinking; a ship body inside chamber 0102 with a space for axially rotating the watertight standby chamber; a support mechanism 0103 supporting such that the watertight standby chamber axially rotates in the ship body inside chamber; and a weight 0104 disposed near the bottom surface of the watertight standby chamber so as to maintain the watertight standby chamber substantially in a horizontal position.