To provide a stabilized product without reducing an operation speed by providing heating distance adjusting means for adjusting a distance between a heater of an infrared drying apparatus and a cloth such that water content in the cloth falls within a predetermined range.

In a hot flue coloring machine 1, a cloth F supplied to a coloring processing apparatus 3 of an application apparatus 2 is dipped in a coloring solution D, and is then drawn with a drawing roller 4 such that water thereof becomes about 60% and is sent to an infrared drying apparatus. In the infrared drying apparatus 5 a plurality of infrared heaters H,... are disposed along a passage of the cloth F, and are movably supported in a direction where these heaters H go to or away from the passage of the cloth F. Heating distance adjusting means 10 adjusts the distance between it and the cloth F by moving the heater H. A moisture meter 20 is provided in the vicinity of an outlet of the infrared drying apparatus 5, and the apparatus 5 is controlled such that the water content of the cloth F becomes about 30%. The cloth F going out from the infrared drying apparatus 5 is sent into a specific drying apparatus 30.