An apparatus for continuously treating hide, leather and pieces of similar material by subjecting the pieces to be treated to exposure to a liquid treating agent selected to effect at least one of a tanning, post-tanning, oiling, fat-liquoring, surface dyeing, through dyeing and impregnating treatment in which pieces to be treated are successively fed to and through a liquid treating agent containing a treatment zone while the movement of the pieces through the zone is so guided that all surfaces of the pieces are exposed to umimpeded contact with the liquid treating agent and just prior to leaving the treatment zone, the leading ends of the successive pieces are grasped by and fed through cooperating pressing rollers to squeeze out excess liquid therefrom as they are leaving the treatment zone. The pieces leaving one treatment zone can be fed to and through a succeeding treatment zone containing the same or a different liquid treating agent and the intensity of the treating action can be increased by heating and/or subjecting the liquid within the zone to ultrasonic excitation or vibration.