Abstract: The present invention relates to acrylic fibers each having a Y-type cross section which consist of an acrylic polymer constituted of at least 50% by weight of acrylonitrile, characterized in that the Y-type cross section is constructed substantially of three rectangles and when the thickness values of the middle part, innermost part, and outermost part of each component rectangle are represented by d.sub.0, d.sub.1, and d.sub.2, respectively, the ratios of d.sub.1 /d.sub.0 and d.sub.2 /d.sub.0 are each in the range of 0.95 to 1.05, and a process for producing the same comprising discharging an organic solvent solution which contains an acrylic polymer constituted of at least 50% by weight of acrylonitrile, dissolved at a concentration of 22 to 30% by weight, and has a viscosity of 200 to 500 poises, through spinneret holes each having a Y-type cross section constructed substantially of three rectangles, into a coagulating liuqid composed of an organic solvent and water at a spinning draft of 1.1 to 1.

Abstract: An acrylic fiber having an irregular form section and a ramie-like feeling, wherein the section of the fiber has unmethodical surface unevenness and has at least two concave parts which has a ratio of the length l of a perpendicular from a tangental line between adjacent convex parts of said unevenness to the deepest part of the concave part to the diameter D.sub.1 of a circumscribed circle: l/D.sub.1 of 0.05 or more, and the surface of said fiber is covered with many discontinuous creases having an average width of 1.mu. or more provided along the lengthwise direction of the fiber, and process for producing the same.