OPTICS-USE RESIN MOLDED BODY PRODUCTION METHOD, RESIN FIBER PRODUCTION METHOD, AND RESIN FIBER PRODUCTION APPARATUS

An optical resin formed body manufacturing method of the present invention includes: (i) depressurizing an inside of a container holding a molten optical resin; (ii) pressurizing the inside of the container holding the molten optical resin; and (iii) shaping the optical resin taken out of the container into a given shape. The steps (i) and (ii) are sequentially performed once each or are alternately performed two or more times each. In the step (i), a duration t1 [min] of the depressurization of the inside of the container is set such that the duration t1 and a viscosity µ1 [Pa*s] of the molten optical resin satisfy a relation µ1/t1 < 200. In the step (ii), a duration t2 [min] of the pressurization of the inside of the container is set such that the duration t2 and a viscosity µ2 [Pa*s] of the molten optical resin satisfy a relation µ2/t2 < 200. The viscosity µ1 is a viscosity of the optical resin at a shear rate of 0.05 s-1 at a temperature in the container in the step (i). The viscosity µ2 is a viscosity of the optical resin at a shear rate of 0.05 s-1 at a temperature in the container in the step (ii).