The purpose of the present invention is to provide a phosphorus-containing compound having reactivity with a glycidyl group, specifically a phosphorus-containing compound represented by general formula (I). (In the formula, m represents a numerical value of 1 to 10; R1 and R2 independently represent a hydrogen atom, an alkyl group or an aryl group; R3 represents an alkyl group, an alkanediyl group, an alkanetriyl group, an alkanetetrayl group or an aromatic group; X represents an oxygen atom or a sulfur atom; Y represents an oxygen atom, a sulfur atom or —NR4—; and R4 represents a hydrogen atom, an alkyl group or an aryl group.)