A phosphorous-containing compound is represented by Formula (I): wherein n is an integer ranging from 1 to 4; R1 represents hydrogen or a linear or branched C1-C4 alkyl group, and a plurality of R1s are the same or different when n is larger than 1; R2 represents hydrogen, or wherein Ep is an epoxy resin moiety; or represents wherein Ar represents a linear or branched C1-C12 alkyl group or a C6-C12 aryl group; and R3 represents hydrogen or methyl.