A phthalocyanine compound which is represented by a free acid of the following formula, ##STR1## wherein Pc is a metal-free or metal-containing phthalocyanine residue, W is a group of ##STR2## in which R' and R" are independently a hydrogen atom or a methyl or ethyl group, and n is an integer of from 2 to 6, R is an unsubstituted or substituted lower alkyl group, A is an unsubstituted or substituted phenylene or naphthylene group, Y is a group of --SO.sub.2 CH.dbd.CH.sub.2 or --SO.sub.2 CH.sub.2 CH.sub.2 Z in which Z is a group capable of being split by the action of an alkali, a is a positive number of from 1 to 3, and b and c are independently a positive number of from 0 to 3, provided that a, b and c statisfy 0