A coating of niobium oxide, zirconium titanate, or nickel titanate is formed on at least a part of a surface of a jet pump member constituting a jet pump serving as a reactor internal structure of a boiling water reactor. Further, a solution containing, e.g., a niobium compound is applied to at least a part of the surface of the jet pump member constituting the jet pump, and the jet pump member coated with the solution is heat-treated to form a coating of, e.g., niobium oxide. With this configuration, the jet pump member constituting the jet pump of the boiling water reactor is provided such that deposition of crud can be sufficiently suppressed on the jet pump member.