To easily and inexpensively manufacture a brake drum by using a press apparatus.

A method of forming a tube-wall flange includes: a step in which a flange 12 is formed by bending an opening edge of a tube wall 11 outward nearly at right angles; a step in which the flange 12 is cut at the inner peripheral boundary face 13 between the flange 12 and the tube wall 11 and that flange 12 is moved to the outer peripheral position of a tube wall 11 a certain distance away from the opening end along the tube wall surface; and a step in which the inner peripheral end of the flange 12 is forced into the tube-wall surface by compressing the flange 12 from an outer peripheral direction.