NOVELTY - Multiple stirring units (2,3,5) each consisting of stirring blade fixed to a stirring shaft, are connected in series. A drive mechanism (15) is provided to automatically rotate the shaft in forward and reverse directions alternatively. A chemical agent injection port (6) is arranged between the biomass substance supply unit (1) and a liquefied product ejection outlet.    USE - For manufacturing liquefied product such as resin raw material, fuel, chemical substance, using biomass substance such as agricultural waste products, saccharides, lignocelluloses, timber and used paper, starch and saccharides and chaff, wheat bran, bean curd lees, rice bran, foodstuffs and foodstuff industry waste material or cellulose acetate, denaturation starch.    ADVANTAGE - High quality liquefied product is efficiently manufactured using the biomass substance, at low cost. The stirring effect of the biomass substance and chemical agent is improved, by the simplified arrangement of the stirring units. The installation space of the stirring units is reduced.    DETAILED DESCRIPTION - The chemical agent reacts with the biomass substance to produce liquefied product. A liquefaction reaction portion is arranged between the chemical agent injection port and the outlet, to liquefy the biomass substance using the predetermined liquefying reaction temperature. A reaction terminator supply unit (7) supplies reaction terminator to stop the liquefaction reaction of biomass substance. The volatile components such as unreacted chemical agent and moisture content, is removed by a volatile component removal unit (8) arranged between reaction terminator supply unit and outlet. A heating section is arranged at downstream side of a mixing section which mixes the biomass substance and chemical agent. The stop time (Ts) during switching of shaft rotation, is set by the formula, 0at mostTsless thant+2, where t is the right time of stirrer after stopage of drive mechanism. The rotation time (Tf) of the shaft in forward direction is set by the formula, 0less thanTfless than 0.2asterisk(60p)/(NK), where p is the pitch number of stirring blade, N is the rotational speed of stirring unit and K is coefficient (0less thankat most1). The rotation time (Tr) of the shaft in reverse direction is set by the formula, 0less thanTrless thanTmin, Tmaxless thanTrless thanTf. An INDEPENDENT CLAIM is also included for manufacturing method of liquefied product.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of the liquefied product manufacturing apparatus. (Drawing includes non-English language text).    biomass substance supply unit (1)    stirring unit (2,3,5)    chemical agent injection port (6)    reaction terminator supply unit (7)    volatile component removal unit (8)    drive mechanism (15)