An improved method of manufacturing a strut member for use in a strut device of the drum brake, having two strut members and a connecting member provided with a threaded portion for linking both, to function as an adjustor of the shoe clearance. This manufacturing method comprises as least the following two processes: (a) forming a flat plate-like portion partially on a length of a tube while producing a through bore therein as a displaced space, by inserting a mandrel substantially concentrically into a tube material, pressing or squeezing a portion of the tube in the diametrical direction in such a manner that the inside of the tube is pressed onto the mandrel for producing the displaced space therein, after retracting the mandrel until the inside surface of the tube at upper and lower portion thereof on either side of the displaced space closely contact to each other; and (b) forming a cut-out, ranging from the extremity of the tube to a part of the flattened portion, such that the through bore can have the opening thereof at the bottom of the cut-out to be able to engage with the web portion of a brake shoe.