With regard to fire protection for exterior walls of a building, only ‘fire-resistive performance’ is considered, according to the current building standard law of Japan. And, fire propagation along combustible material installed at external side of fire-resistive wall is not specifically evaluated, even though combustion of external cladding could cause acceleration of the fire propagation along exterior walls, in some cases. In this study, new test method for evaluation of fire propagation along combustible cladding, was proposed and also, test specimens produced referring to facade wall with exterior thermal insulation were burned in order that the application of the method is demonstrated.