To prevent the steam in a steam treatment chamber from causing mutual interference with the hot air in a drying chamber to efficiently adjust the heat source by using a common heater for the temperature retention and drying in the dress-finishing forming process in a tunnel finisher.

An open space 3 is provided between a steam treatment chamber 1 and a drying chamber 2 in both of which the products pass through so that the hot air in the drying chamber 2 may circulate in the partition walls of the steam treatment chamber. The mutual interference between the steam and the hot air can be perfectly inhibited and simultaneously a heater and a sirocco- fan for the hot air circulation are utilized for the drying hot air and the temperature retention hot air to minimize the space for installation of the hot air mechanism. Thus, the apparatus can be miniaturized and a far-much excellently finished product can be obtained.