A method for producing a phosphoric acid ester, comprising: a step: a step of allowing phosphorus oxytrihalide represented by Formula (wherein X is halogen) to react with a phenol compound or naphthol compound represented by Formula (wherein R 1, R 2, R 3, R 4 and R 5 are independent from one another, and are a hydrogen atom, or a C 6-12 aryl group which may be substituted with a straight or branched-chain C 1-4 alkyl group, and alternatively R 1 and R 2, R 2 and R 3, R 3 and R 4, or R 4 and R 5 may form a 6-membered ring together with the carbon atoms of the benzene ring to which these groups are bound, provided that R 1, R 2, R 3, R 4 and R 5 are not hydrogen atoms at the same time), at a molar ratio of 1.1-3.0:1 in the presence of a metal halide, to produce a mono-substituted phosphorodihalidate represented by Formula (wherein X, R 1, R 2, R 3, R 4 and R 5 have the same meaning as the above-described meaning); and a step: a step of allowing the mono-substituted phosphorodihalidate obtained in the step represented by the Formula to react with a diol compound represented by Formula (wherein R 6 and R 7 are independent from each other, and are a hydrogen atom, a straight or branched-chain C 1-6 alkyl group, or a C 6-12 aryl group which may be substituted with a straight or branched-chain C 1-4 alkyl group) so as to perform a dehydrohalogenation reaction without using a hydrogen halide scavenger, to produce a phosphorus compound represented by Formula (wherein R 1, R 2, R 3, R 4, R 5, R 6 and R 7 have the same meaning as the above-described meaning). a step: a step of allowing phosphorus oxytrihalide represented by Formula (wherein X is halogen) to react with a phenol compound or naphthol compound represented by Formula (wherein R 1, R 2, R 3, R 4 and R 5 are independent from one another, and are a hydrogen atom, or a C 6-12 aryl group which may be substituted with a straight or branched-chain C 1-4 alkyl group, and alternatively R 1 and R 2, R 2 and R 3, R 3 and R 4, or R 4 and R 5 may form a 6-membered ring together with the carbon atoms of the benzene ring to which these groups are bound, provided that R 1, R 2, R 3, R 4 and R 5 are not hydrogen atoms at the same time), at a molar ratio of 1.1-3.0:1 in the presence of a metal halide, to produce a mono-substituted phosphorodihalidate represented by Formula a step of allowing phosphorus oxytrihalide represented by Formula (wherein X is halogen) to react with a phenol compound or naphthol compound represented by Formula (wherein R 1, R 2, R 3, R 4 and R 5 are independent from one another, and are a hydrogen atom, or a C 6-12 aryl group which may be substituted with a straight or branched-chain C 1-4 alkyl group, and alternatively R 1 and R 2, R 2 and R 3, R 3 and R 4, or R 4 and R 5 may form a 6-membered ring together with the carbon atoms of the benzene ring to which these groups are bound, provided that R 1, R 2, R 3, R 4 and R 5 are not hydrogen atoms at the same time), at a molar ratio of 1.1-3.0:1 in the presence of a metal halide, to produce a mono-substituted phosphorodihalidate represented by Formula (wherein X, R 1, R 2, R 3, R 4 and R 5 have the same meaning as the above-described meaning); and a step: a step of allowing the mono-substituted phosphorodihalidate obtained in the step represented by the Formula to react with a diol compound represented by Formula (wherein R 6 and R 7 are independent from each other, and are a hydrogen atom, a straight or branched-chain C 1-6 alkyl group, or a C 6-12 aryl group which may be substituted with a straight or branched-chain C 1-4 alkyl group) so as to perform a dehydrohalogenation reaction without using a hydrogen halide scavenger, to produce a phosphorus compound represented by Formula (wherein R 1, R 2, R 3, R 4, R 5, R 6 and R 7 have the same meaning as the above-described meaning).