Product recipes in which a treatment procedure and treatment conditions of heat treatment of product wafers are specified are created timely. Dummy recipes in which a treatment procedure and treatment conditions of heat treatment of dummy wafers are specified are also created. Each of the product recipes and a corresponding one of the dummy recipes are stored in association with each other. Dummy treatment of a dummy wafer starts when a controller receives an advance notice signal indicating that product wafers will arrive at a heat treatment apparatus. The dummy wafers are stored in a dummy carrier permanently installed on a load port exclusive to the dummy carrier. The dummy treatment is performed in accordance with a dummy recipe associated with a product recipe corresponding to the product wafers scheduled to arrive at the heat treatment apparatus.