PURPOSE: To provide a strut positioning device of properly performing carry-in setting of a car body required part by centering a plurality of stud bolts in an upper surface of an upper part insulator of a strut, held by a strut building robot, to a specified position, and positioning a holding condition of the strut by the building robot finally corrected to a regular direction.

CONSTITUTION: A clamp plate 84, set up on the halfway of strut conveyance of a strut building robot for holding a strut 3 by teaching action carried in set to a required part of a body of an automobile and having bolt centering patch surfaces 81b, 81c with a side surface part of two stud bolts 3a in an upper surface of an upper part insulator 3b of this strut 3 brought into contact further forcedly pressing the above-mentioned two stud bolts 3a to these bolt centering patch surfaces 81b, 81c to perform centering positioning, and a cylinder 88 for clamping this clamp plate are provided.