PURPOSE: To provide the titled fiber having bacteriostatic and mildewstatic activity, low toxicity and low irritation to the skin, and suitable for sanitary use, by wet-spinning an acrylic polymer, drawing the fiber, washing with water, and applying a specific phenolic compound to the fiber.

CONSTITUTION: A bacteriostatic acrylic synthetic fiber can be obtained by (1) wet-spinning an acrylic polymer having an acrylonitrile content of ≥40wt% followed by drawing and washing with water, and (2) applying 0.01W5wt%, based on the weight of the fiber, of 3-methyl-4-isopropylphenol and/or 2-isopropyl-5-methylphenol to the swollen gelled fiber, and drying and heat-treating the fiber. The polymer is preferably the one derived from ≥80wt% of acrylonitrile and ≤20wt% of a vinyl monomer and a monomer contg. sulfonic acid group.