A tank cover and a ship are provided to sufficiently secure fatigue strength of the lower end joined to an upper deck of the body of the ship and to improve the fatigue life. A tank cover(20) covers a protruded part of an upper deck(11) of a tank of an independent spherical shape mounted on a ship in a state of projecting a part on the upper deck of the body of the ship. A reinforced part, the strength of which is reinforced, is formed to a lower end part(23) of the tank cover joined to the upper deck. The reinforced part constitutes a thick-walled part(30) formed by making the lower end part thicker than the other part. The reinforced parts are formed to both ends of a central line of the tank cover in the transverse direction of the body of the ship.
