PURPOSE: To efficiently perform heating and drying of steel-strip by disposing heating rolls, which are formed from steel and into which a heating medium is continuously supplied, in contact with both surfaces of the steel-tape in a continuous processing line of steel-strip.

CONSTITUTION: In a continuous processing line of a cold rolled steel-strip, a heating medium forwarded from a circulating vessel 72 of the heating medium by a circulating pump 73 enters a heat exchanger 75, which is provided in an exhaust duct 43 of a heat treatment line 4 in the processing line, through a feed pipe 75 to perform heat exchange with exhaust gases to be raised in temperature, and then is fed into heating rolls 61 through a piping 76 provided on an outlet side of the heat exchanger. The heating rolls 61 are formed from steel and of a pinch roll type to interpose therebetween the steel-strip S to thereby contact with a small amount of water film, which is left on surfaces of the steel-strip S, thus heating the steel-strip S. Therefore, it is possible to heat the steel-strip by the use of a small amount of heat to efficiently dry the surfaces of the steel-strip. Also, it is possible to more economically perform drying in the case where waste heat in the line is utilized as a heat source.