PROBLEM TO BE SOLVED: To provide a friction resistance reduction device of a ship which enables efficient work during maintenance in a chamber.SOLUTION: A friction resistance reduction device of a ship includes: a chamber 10; an air-supply section serving as a supply source of a gas; and multiple air outlet holes 31. The chamber 10 is a space which communicates with the multiple air outlet holes 31 provided at a bottom 110 of the ship and to which the gas is supplied from the air-supply section. The chamber 10 includes: an opening 130 provided at the bottom 110 of the ship; and a lid 140 which fits in the opening 130 and is fixed thereto.
