PURPOSE: To obtain the subject fiber, having a high mechanical strength and usable in an optional form, such as cut fiber, single yarn or fabric, and useful as vibration damping and water holding materials, etc., by subjecting a hydrous fiber prepared by spinning an aqueous spinning solution of a PVA-based polymer to freezing and thawing treatment.

CONSTITUTION: The objective fiber obtained by carrying out conjugate spinning of an aqueous spinning solution of a PVA-based polymer (preferably having ≥3000 polymerization degree) with a water-coagulable fiber-forming polymer spinning solution (e.g., polyacrylonitrile-, PE-, PP-, polysiloxane or polyester- based polymer) to provide a hydrous fiber and then subjecting the resultant fiber to freezing treatment (preferably at ≤-10°C) and thawing treatment (preferably at 0-30°C).