PURPOSE: To obtain an antistatic sizing agent for fiber, comprising a cationized pullulan, excellent in antistatic effects at a low humidity without discoloring fiber, good in hand and capable of manifesting excellent sizing effects without causing the deterioration in color fastness.

CONSTITUTION: A raw material pullulan is made to react with a cationizing agent selected from formulas I and II (R1 to R3 are hydrocarbon; X and Y are halogen) to provide a cationized pullulan, expressed by formula III [R4 is H or substituent group expressed by formula IV; n is 20-20000; (R1 to R3 are hydrocarbon, R1 and R2 are preferably 1-3C alkyl; R3 is 1-18C alkyl; X is halogen, especially chlorine)] and having preferably a substituent group, expressed by formula IV and present in an amount of ≥0.01 expressed in terms of the degree of substitution based on the anhydroglucose unit. The resultant cationized pullulan is then used as a substrate and a cationic surfactant, as necessary, is added thereto. A textile material such as natural or synthetic fiber is subsequently immersed and treated with the prepared treating solution to afford the objective antistatic sizing agent capable of assuming excellent sizing effects. Trimethylammonium chloride, dimethyloctylammonium chloride, etc., can be exemplified as a common part of NR1R2R3X expressed by formulas I and II.