A semiconductor encapsulation resin composition characterized in comprising: a cyanate ester compound having not less than two cyanato groups in one molecule; a phenolic compound represented by the following general formula: wherein in formula, m represents an integer of 0 to 10; each R 5 independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; each R 6 independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and each R 7 independently represents a group selected from the divalent groups expressed by the following formulae: - CH(CH 3)-, -O-, -S-, -SO 2 -, wherein in the above formulae, each R 4 independently represents a hydrogen atom or a methyl group; at least one of the epoxy resins represented by the following formulae and: wherein in formula, R 8 independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R 9 independently represents a group selected from the divalent groups expressed by the following formulae; and p represents an integer of 0 to 10, and wherein in formula, R 10 independently represents a group selected from the divalent groups expressed by the following formulae; j independently represents an integer of 1 to 6; and k represents an integer of 0 to 10 -CH 2 -, a copolymer obtained by a hydrosilylation reaction of an alkenyl group-containing epoxy compound and an organopolysiloxane represented by the following average formula wherein in formula, R 11 independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms; a is a positive number satisfying 0.01 ≤ a ≤ 1, and b is a positive number satisfying 1 ≤ b ≤ 3, provided that 1.01 ≤ a+b < 4; and at least one kind of compound selected from a tetraphenylborate salt of a tetra-substituted phosphonium compound and a tetraphenylborate salt represented by the following formula wherein in formula, R 15 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a phenyl group; and n 12 represents an integer of 1 to 3, and wherein a molar ratio of phenolic hydroxyl groups in said phenolic compound to cyanato groups in said cyanate ester compound is 0.08 to 0.25, and a molar ratio of epoxy groups in said epoxy resin and said component to cyanato groups in said cyanate ester compound is 0.04 to 0.25. a cyanate ester compound having not less than two cyanato groups in one molecule; a phenolic compound represented by the following general formula: wherein in formula, m represents an integer of 0 to 10; each R 5 independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; each R 6 independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; and each R 7 independently represents a group selected from the divalent groups expressed by the following formulae: - CH(CH 3)-, -O-, -S-, -SO 2 -, wherein in the above formulae, each R 4 independently represents a hydrogen atom or a methyl group; - CH(CH 3)-, -O-, -S-, -SO 2 -, at least one of the epoxy resins represented by the following formulae and: wherein in formula, R 8 independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R 9 independently represents a group selected from the divalent groups expressed by the following formulae; and p represents an integer of 0 to 10, and wherein in formula, R 10 independently represents a group selected from the divalent groups expressed by the following formulae; j independently represents an integer of 1 to 6; and k represents an integer of 0 to 10 -CH 2 -, a copolymer obtained by a hydrosilylation reaction of an alkenyl group-containing epoxy compound and an organopolysiloxane represented by the following average formula wherein in formula, R 11 independently represents a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms; a is a positive number satisfying 0.01 ≤ a ≤ 1, and b is a positive number satisfying 1 ≤ b ≤ 3, provided that 1.01 ≤ a+b < 4; and at least one kind of compound selected from a tetraphenylborate salt of a tetra-substituted phosphonium compound and a tetraphenylborate salt represented by the following formula wherein in formula, R 15 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a phenyl group; and n 12 represents an integer of 1 to 3, and wherein a molar ratio of phenolic hydroxyl groups in said phenolic compound to cyanato groups in said cyanate ester compound is 0.08 to 0.25, and a molar ratio of epoxy groups in said epoxy resin and said component to cyanato groups in said cyanate ester compound is 0.04 to 0.25.