Abstract: A method for the heat treatment of metal strips which comprises heating and cooling a metal strip while allowing the strip to pass through a heat treatment apparatus in a floating manner. When passing through the apparatus in such a manner, the strip is curved in the wave forms in the direction of feed thereof. Such curvatures given to the strip increase the resistance of the strip against buckling stress. The increased resistance of the strip against buckling stress is stronger than the thermal stress produced therein during the heating and cooling treatment so that the strip can be heated and cooled without any wrinkles produced therein.