NOVELTY - A silicone resin composition (C1) comprises a first opposite-terminals-sealed-with-vinyl-group-type silicone resin (Ia); a second opposite-terminals-sealed-with-vinyl-group-type silicone resin (Ib)); alkenyl-group-containing polysiloxane (II); hydro-group-containing polysiloxane (III) having a weight average molecular weight of 100-10000; and a hydrosilylating catalyst.    USE - As silicone resin composition for semiconductor device (claimed) used in light-emitting diode device (LED), for sealing of the electrolyte of pigment-sensitizing solar battery; for forming a dipping agent for general industrial purpose, profiling rubber, molding material, stripping coating agent, addition reaction type silicone rubber or silicone gel such as dental impression material.    ADVANTAGE - The silicone resin composition is low in viscosity, excellent in transparency, capable of obviating discoloration with time and capable of giving a cured material excellent in adhesive properties; provides semiconductor device having excellent in alleviating any thermal stress; can be applied to the pigment-sensitizing solar battery, and enhances its durability.    DETAILED DESCRIPTION - A silicone resin composition (C1) comprises a first opposite-terminals-sealed-with-vinyl-group-type silicone resin of formula H2C=CH-Si(R10)2-O-(Si(R10)2-O)k1-Si(R10)2-CH=CH2 (Ia) and incorporated at a first weight (w1); a second opposite-terminals-sealed-with-vinyl-group-type silicone resin of formula H2C=CH-Si(R11)2-O-(Si(R11)2-O)k2-Si(R11)2-CH=CH2 (Ib) and incorporated at a second weight (w2); alkenyl-group-containing polysiloxane of formula (R12-Si(R13)2-O-)4Si (II); hydro-group-containing polysiloxane of formula (R14)mSiO(4-m)/2(SiO2) (III) having a weight average molecular weight of 100-10000 and including 10-50 mole.% of Q unit of formula -O-Si(-O-)3; and a hydrosilylating catalyst.    R10-R13=1-4C alkyl;    k1=800-900;    k2=(k1+100) to less than 1300;    R14=0.1-95 mole.% of hydro group and the balance of 1-4C alkyl;    m=1-3.    The ratio of w2 to w1 is 0.03-0.2. An INDEPENDENT CLAIM is included for a resin-encapsulated semiconductor device (1) comprising a light-emitting element; and a resin layer (2) sealing the light-emitting element and formed of a cured material of the silicon resin composition.    DESCRIPTION OF DRAWING(S) - The figure shows a diagram schematically illustrating the structure of a semiconductor device.    Semiconductor device (1)    Resin layer (2)    Conductive wire (3)    Substrate (4)    Inner electrode (5a)    Outer electrode (5b)    Diode chip (6)