PURPOSE: To surely and strongly fix a flange to the opening end part of a cylindrical member by forming a flange in such a state that the connection part provided so as to extend from the opening end part of the cylindrical member through the flat part thereof is integrally embedded in the flange.

CONSTITUTION: An air introducing pipe 2 having a structure equipped with a flat part 8 and a connection part 10 is molded by blow-molding using a molding material such as glass fiber-containing nylon. When the movable mold 16 to which the air introducing pipe 2 is set is registered with a fixed mold 12 to form a molding cavity 14, the molding material, for example, nylon mixed with glass fibers or ceramics is injected in the cavity to fill the cavity and cooled and solidified to mold the flange 14. By this method, an air intake for a car is obtained.