To provide a polytetrafluoroethylene (PTFE) fiber having a fiber section with a plurality of convexities or a flat fiber section of which the each has not been obtained yet, to provide a method for producing the same, and to provide a cloth given by using the same.

This PTFE fiber having the fiber section with the plurality of the convexities or the flat fiber section is produced by matrix spinning processes. The method for producing the PTFE fiber comprises using viscose as a matrix and spinning the fiber by discharging a liquid mixture of the viscose and an aqueous PTFE dispersion into a coagulation bath which is regulated to contain specified components and have a specified concentration through a nozzle having a plurality of the convexities, wherein the spun fiber is characteristically baked so that the fiber is passed through a semi-baking process at a specified temperature, while being relaxed at a specified relaxation ratio, and then baked at a specified temperature. The cloth having collecting properties of fine dust more excellent than ever is obtained by using the PTFE fiber having the profiled section.

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