Provided is a novel alkyl sulfate ester having a carbonyl group, or a salt of this alkyl sulfate ester. A compound which is characterized by being represented by formula R1-C(=O)-(CR2 2)n-(OR3)p-(CR42)q-L-OSO3X. (In the formula, R1 represents an optionally substituted linear or branched chain alkyl group having 1 or more carbon atoms, or an optionally substituted cyclic alkyl group having 3 or more carbon atoms; each of R2 and R4 independently represents H or a substituent; R3 represents an optionally substituted alkylene group having 1-10 carbon atoms; n represents an integer of 1 or more; each of p and q independently represents an integer of 0 or more; X represents H, a metal atom, NR5 4, an optionally substituted imidazolium, an optionally substituted pyridinium or an optionally substituted phosphonium; R5 represents H or an organic group; L represents a single bond, -CO2-B-*, -OCO-B-*, -CONR6-B-*, -NR6CO-B-* or -CO- (excluding a carbonyl group contained in -CO2-B-, -OCO-B-, -CONR6-B- and -NR6CO-B-); B represents a single bond or an optionally substituted alkylene group having 1-10 carbon atoms; R6 represents H or an optionally substituted alkyl group having 1-4 carbon atoms;and * indicates the side which is bonded to -OSO3X in the formula.)