A heating method for a band-shaped body transported in a constant conveying direction in a heating zone so as to heat it, comprises: detecting whether or not a portion of the band-shaped body is passing through the heating zone, at which portion at least one of width and thickness of the band-shaped body changes; before detecting the portion pass into the heating zone, setting a first supplied heat quantity based on dimensions of the first band-shaped body on a downstream side of the portion in the conveying direction, and supplying heat with the first supplied quantity to the band-shaped body in the heating zone; and after detecting that the portion has passed into the heating zone, setting a second supplied heat quantity based on dimensions of the second band-shaped body on an upstream side of the portion relative to the conveying direction, and supplying heat with the second supplied quantity to the band-shaped body in the heating zone, so as to adjust a temperature history of the band-shaped body so that the temperature history is approximately uniform on both upstream and downstream sides of the portion.