According to the present invention, in adhering a belt edge tape (1) which is interposed between belt layers of a tire, press rollers surely adhere by pressing the belt edge tape (1) to a building drum (D) while preventing the press rollers from being caught by end portions of inclined cords which constitute a belt. For this end, in adhering the belt edge tape (1) to both respective side edge portions of the belt on the outer peripheral surface of the building drum by supplying the belt edge tape (1) toward the outer peripheral surface of the building drum by pressing using an extruder (10) which constitutes a supply device facing the building drum (D) in an opposed manner and by pressing the belt edge tape (1) to the building drum (D) using a press roller (15a), (15b) on a leading side as viewed from a position where the belt edge tape (1) is supplied in the rotational direction of the building drum (D), the building drum (D) is rotated in the direction that end portions of the reinforcing cords on the side edge portion of the belt which constitutes a tape adhering side are positioned on a trailing side in the rotational direction of the building drum (D) thus adhering the belt edge tape (1) to the side edge portion.