PURPOSE: To obtain a spinning block of stably feeding a polymer having uniform temperature and viscosity to a spinning pack, stabilizing spinning tone and improving yarn qualities by inserting a heat pipe to uniform temperature to a branching plate for polymer distribution.

CONSTITUTION: A spinning block 8 is equipped with a branching plate 12 for polymer distribution and a great number of heat pipes 19 thermally connecting the branching plate to the outer peripheral part surrounded by a spinning block heating medium tank 30 are inserted into the branching plate 12. When temperature unevenness occurs in the branching plate 12, a low-temperature part of the branching plate 12 is heated by heat transferred from the heat pipes 19, heat of high-temperature part is released from the heat pipes 19 to the low- temperature part to uniformize temperature of the branching plate.