To eliminate the need for transferring laundry during transition from a preliminary drying process to a main drying process by improving a two-step drying method and apparatus such that a drying process is separated into preliminary drying and main drying processes.

A first dryer A and a second dryer B are provided and interconnected by a first exhaust supply line 15A and a second exhaust supply line 15B. The main drying is carried out by one of the dryers (first dryer A in this example) and its exhaust is supplied to the second dryer B via the first exhaust supply line 15A (as shown by a number of small arrows), so that the preliminary drying is carried out using the second dryer B. After the main drying by the first dryer A is complete, exhaust flow passages are switched from one to the other by the operation of switching dampers 14A and 14B, so that the first dryer A replaces the laundry and performs the preliminary drying, while the second dryer B performs the main drying without replacing the laundry.