An apparatus for supplying a definite amount of a treating liquid to a textile product continuously, including a liquid retaining roll having a fine uneven surface or closely spaced small holes all over its surface to retain a treating liquid on the surface thereof, a device to supply a treating liquid to the liquid retaining roll by eliminating the flock and hards of the textile product and other dust adhering thereon, a doctor roll in contact with the liquid retaining roll to control the treating liquid adhering to the liquid retaining roll to a definite amount by pressing, a rubber roll to guide a textile product to be treated continuously, the rubber roll being in pressure contact with the said liquid retaining roll by putting the textile product therebetween to transfer a prescribed amount of the treating liquid to the textile product, and a device to clean the surface of the rubber roll by utilizing a circulated part of the said treating liquid.