A method of manufacturing acrylic fibers free from delustering in boiling water, comprises the steps of forming a spinning solution by dissolving in a solvent of acetone, acetonitrile, dimethylformamide and mixtures thereof, (a) a copolymer consisting of (1) 30 - 80% acrylonitril and (2) 70 - 20% vinyl chloride or vinylidenechloride, or (b) a tripolymer consisting of (1), (2) and (3) 3.0% or less by weight of ethylenically unsaturated monomer having hydrophilic groups, and adding one or more compound selected from the group of (1) homopolymer or copolymer of glycidyl methacrylate and (2) specific organic tin compounds, and spinning said spinning solution into a first bath consisting of 60% or less said organic solvent-water and leading said yarn in a 2nd bath consisting of 61 - 85% said organic solvent-water and then in a 3rd and more bath consisting of less than 60% said organic solvent-water and drying, drawing out and annealing said yarn by ordinary methods.