the anode side electrode roll 10 and the cathode side electrode roll 12 both comprising an electrical conductor are opposedly disposed with a certian distance therebetween an anode and cathode of the dc power supply 14 are respectively connected t othe electrode rolls 10 12 the cloth 16 to be treated is dipped in the treating solution and is then squeezed in such a manner between rollers 24 and 26 as to be uniformly impregnated with the treating solution the wet cloth 16 is then disposed over and between each of at least two electrode rolls 10a 12a in applying a dc voltage from the dc power suppy 14 to the at least two electrode rolls10a 12a because cloth 16 imprengated with the treating solution is in electrical contact with the two electrode rolls 10 12 a dc current passes from the anode of the dc power supply 14 to the cathode thereof by way of the anode side electrode roll 10a through the treating solution impregnated into the cloth 16 and from the cathode side electrode roll 12 at this time the temperature of the impregnated cloth 16 is raised by heat generation in the treating solution because of the electric resistance of the solution thus the temperature can be easily raised e g to 90 u00b0 c to 100 u00b0 c necessary for dyeing just by controlling the applied voltage from the dc power supply 14 fig1.