The present invention relates to a hydrophilizing agent for producing a self-emulsifying polyisocyanate composition, the hydrophilizing agent comprising an anionic compound represented by the following formula (1): wherein X represents a sulfo group or a hydroxysulfonyloxy group, R1 represents a straight-chain or branched alkylene group, and R2 represents a straight-chain or branched alkyl group; the total number of carbon atoms included in R1 and R2 is 6 or more and less than 14, and one or two or more carbon atoms in the groups R1 and R2 are optionally replaced with an oxygen atom(s).