Abstract: An apparatus for fluid treatment of a fiber product is provided in which an endless fiber product is circulated in a predetermined direction within a treatment bath in a treatment vessel, characterized in that said apparatus comprises a fiber product residence section composed of a horizontal outer tube communicating with the side of the lower portion of said treatment vessel and a perforated tube concentrically provided inside said outer tube, a high-speed revolving reel for running said fiber product provided outside said treatment bath in said treatment vessel and a tube for transferring said fiber product provided with a treatment fluid jet nozzle for high-speed transfer of said fiber product so provided outside said treatment vessel as to connect the rear portion of said reel in said treatment vessel to the tip of said horizontal outer tube.