Since a vessel resistance reduction device includes: a gas chamber (41) provided inside a hull (10); a vessel bottom shell plate (27) which is a defining wall defining an inside of the gas chamber (41) and an outside of the hull (10); an air blowing port (42) provided at the vessel bottom shell plate (27); and first guide plates (51, 52) which are guide members provided at a rear side of the hull (10) in the air blowing port (42), a friction resistance reduction effect can be improved.
