A heating method and apparatus for a band-shaped body transported in a constant conveying direction in a heating zone so as to heat the band-shaped body is provided. The method includes detecting whether a portion of the band-shaped body at which width and/or thickness changes is passing through the heating zone setting a first supplied heat quantity, and supplying heat with the first supplied quantity to the band-shaped body in the heating zone; and setting a second supplied heat quantity, and supplying heat with the second supplied quantity to the band-shaped body in the heating zone. The method also includes increasing or decreasing at least one of air flow rate or temperature of the heated air stream. The apparatus includes an air flow ratio changing unit which maintains a constant sum of introduced air stream flow rate and bypass air stream flow rate.