A resin composition for an electric/electronic component, comprising: a polyorganosiloxane that contains a mercaptoalkyl group bonded to a silicon atom and has a viscosity at 23°C of 20 to 3,000 cP; a polyorganosiloxane containing an aliphatic unsaturated group wherein the polyorganosiloxane includes: a linear polyorganosiloxane represented by the formula: wherein each R 1 is independently an aliphatic unsaturated group, each R is independently a C1-C6 alkyl group or a C6-C12 aryl group, and n is a value such that the viscosity at 23°C is 100 to 12,000 cP; and optionally a branched polyorganosiloxane including a SiO 4/2 unit, an R' 3 SiO 1/2 unit and an R' 2 SiO 2/2 unit, and optionally further an R'SiO 3/2 unit wherein each R' independently represents a C1-C6 alkyl group or an aliphatic unsaturated group, and at least three R' groups per molecule of the branched polyorganosiloxane are aliphatic unsaturated groups; a photoreaction initiator; a chemically surface-treated silica having a BET specific surface area of 50 to 250 m 2 /g and a pH of 5.0 to 9.0; and a polyoxyalkylene glycol in which an alkylene unit is a linear or branched alkylene group having 2 to 4 carbon atoms, and/or a derivative of the polyoxyalkylene glycol, wherein the ratio of the number of mercaptoalkyl groups in to the total number of aliphatic unsaturated groups in is 0.45 to 2.00, the content of is 0.5 to 26 parts by mass relative to 100 parts by mass of, the proportion of the content of is 0.001 to 1.0 mass% relative to the total mass of to, and the viscosity at 23°C is 500 to 100,000 cP, where all viscosities are determined in accordance with the method outlined in the description. a polyorganosiloxane that contains a mercaptoalkyl group bonded to a silicon atom and has a viscosity at 23°C of 20 to 3,000 cP; a polyorganosiloxane containing an aliphatic unsaturated group wherein the polyorganosiloxane includes: a linear polyorganosiloxane represented by the formula: wherein each R 1 is independently an aliphatic unsaturated group, each R is independently a C1-C6 alkyl group or a C6-C12 aryl group, and n is a value such that the viscosity at 23°C is 100 to 12,000 cP; and optionally a branched polyorganosiloxane including a SiO 4/2 unit, an R' 3 SiO 1/2 unit and an R' 2 SiO 2/2 unit, and optionally further an R'SiO 3/2 unit wherein each R' independently represents a C1-C6 alkyl group or an aliphatic unsaturated group, and at least three R' groups per molecule of the branched polyorganosiloxane are aliphatic unsaturated groups; a linear polyorganosiloxane represented by the formula: wherein each R 1 is independently an aliphatic unsaturated group, each R is independently a C1-C6 alkyl group or a C6-C12 aryl group, and n is a value such that the viscosity at 23°C is 100 to 12,000 cP; and optionally wherein each R 1 is independently an aliphatic unsaturated group, each R is independently a C1-C6 alkyl group or a C6-C12 aryl group, and n is a value such that the viscosity at 23°C is 100 to 12,000 cP; a branched polyorganosiloxane including a SiO 4/2 unit, an R' 3 SiO 1/2 unit and an R' 2 SiO 2/2 unit, and optionally further an R'SiO 3/2 unit wherein each R' independently represents a C1-C6 alkyl group or an aliphatic unsaturated group, and at least three R' groups per molecule of the branched polyorganosiloxane are aliphatic unsaturated groups; a photoreaction initiator; a chemically surface-treated silica having a BET specific surface area of 50 to 250 m 2 /g and a pH of 5.0 to 9.0; and a polyoxyalkylene glycol in which an alkylene unit is a linear or branched alkylene group having 2 to 4 carbon atoms, and/or a derivative of the polyoxyalkylene glycol, wherein