and peeled from the support to form a film 57 the film 57 is further dried and wound up to a roll 0123 fig4 is a sectional view schematically illustrating the apparatus of the second embodiment 3 to 5 shown in fig a swelled mixture of a polymer and a solvent 71 is extruded by a fiber extruding die 43 the extruded fiber 44 of the mixture is dropped into a cooling and separating vessel 58 fig3 and 4 show only one fiber 44 for convenience of description however it is possible and preferred to extrude many fibers simultaneously by using an extruding die the cooling and separating vessel 58 contains a cooling liquid 61 further a slanted conveyer belt made of a net 62 is placed in the cooling and separating vessel 58 except that the end of the belt is placed outside the vessel the conveyer belt is rotated by a driving roller 63 the dropped fiber of the mixture 44 is immediately cooled with the cooling liquid 61 in the vessel 58 the cooled fiber 64 is separated from the cooling liquid 61 while conveying the fiber on the belt 62 the separated fiber 64 is dropped into a warming vessel 45 a guide board 65 and a scraper 66 are attached to the conveyer belt 62 the board 65 guides the dropped fiber 44 to the conveyer belt 62 the scraper 66 scarps.