An addition-curable silicone resin composition comprising: (A-1) a linear organopolysiloxane having at least two alkenyl groups per molecule; (A-2) a branched organopolysiloxane of the average compositional formula below which has at least two alkenyl groups per molecule (R 1 3-t R 2 t SiO 1/2) p (R 3 2 SiO 2/2) q (R 3 SiO 3/2) r (SiO 4/2)s wherein R 1 is independently an alkenyl group of 2 to 8 carbon atoms, R 2 is independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 12 carbon atoms which contains no aliphatic unsaturated bonds, each R 3 is independently R 1 or R 2, with at least two of the R 3 groups on the molecule being R 1, p, q, r and s satisfy the conditions 0.01 ≤ p ≤ 0.6, 0 ≤ q, 0 ≤ r and 0.1 ≤ s ≤ 0.9, with the proviso that p+q+r+s = 1, and t satisfies the condition 0 ≤ t < 3; an organohydrogenpolysiloxane of the average compositional formula below which has a content of low-molecular-weight siloxane having a degree of polymerization of up to 10 and at least one SiH group per molecule of 5 wt % or less (R 4 3 SiO 1/2) e (SiO 4/2) f wherein each R 4 is independently a hydrogen atom or a methyl group, with at least two of all the R 4 groups being hydrogen atoms, e and f satisfy the conditions 0.01 ≤ e ≤ 0.6 and 0.4 ≤ f ≤ 0.99, with the proviso that e+f = 1, wherein the source of the SiO 4/2 units in the organohydrogenpolysiloxane is tetramethoxysilane or a partial hydrolyzate/condensate of tetraethoxysilane or both; and an addition reaction catalyst. (A-1) a linear organopolysiloxane having at least two alkenyl groups per molecule; (A-2) a branched organopolysiloxane of the average compositional formula below which has at least two alkenyl groups per molecule (R 1 3-t R 2 t SiO 1/2) p (R 3 2 SiO 2/2) q (R 3 SiO 3/2) r (SiO 4/2)s wherein R 1 is independently an alkenyl group of 2 to 8 carbon atoms, R 2 is independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 12 carbon atoms which contains no aliphatic unsaturated bonds, each R 3 is independently R 1 or R 2, with at least two of the R 3 groups on the molecule being R 1, p, q, r and s satisfy the conditions 0.01 ≤ p ≤ 0.6, 0 ≤ q, 0 ≤ r and 0.1 ≤ s ≤ 0.9, with the proviso that p+q+r+s = 1, and t satisfies the condition 0 ≤ t < 3; wherein R 1 is independently an alkenyl group of 2 to 8 carbon atoms, R 2 is independently a substituted or unsubstituted monovalent hydrocarbon group of 1 to 12 carbon atoms which contains no aliphatic unsaturated bonds, each R 3 is independently R 1 or R 2, with at least two of the R 3 groups on the molecule being R 1, p, q, r and s satisfy the conditions 0.01 ≤ p ≤ 0.6, 0 ≤ q, 0 ≤ r and 0.1 ≤ s ≤ 0.9, with the proviso that p+q+r+s = 1, and t satisfies the condition 0 ≤ t < 3; an organohydrogenpolysiloxane of the average compositional formula below which has a content of low-molecular-weight siloxane having a degree of polymerization of up to 10 and at least one SiH group per molecule of 5 wt % or less (R 4 3 SiO 1/2) e (SiO 4/2) f wherein each R 4 is independently a hydrogen atom or a methyl group, with at least two of all the R 4 groups being hydrogen atoms, e and f satisfy the conditions 0.01 ≤ e ≤ 0.6 and 0.4 ≤ f ≤ 0.99, with the proviso that e+f = 1, wherein the source of the SiO 4/2 units in the organohydrogenpolysiloxane is tetramethoxysilane or a partial hydrolyzate/condensate of tetraethoxysilane or both; and wherein each R 4 is independently a hydrogen atom or a methyl group, with at least two of all the R 4 groups being hydrogen atoms, e and f satisfy the conditions 0.01 ≤ e ≤ 0.6 and 0.4 ≤ f ≤ 0.99, with the proviso that e+f = 1, wherein the source of the SiO 4/2 units in the organohydrogenpolysiloxane is tetramethoxysilane or a partial hydrolyzate/condensate of tetraethoxysilane or both; and an addition reaction catalyst.