The present invention relates to a curable silicone composition comprising: (A) an organopolysiloxane represented by the average unit formula: (R13SiO1/2)a(R12SiO2/2)b (R2SiO3/2)c (R3SiO3/2)d, wherein, R1 are the same or different alkyl groups having from 1 to 12 carbons, alkenyl groups having from 2 to 12 carbons, aryl groups having from 6 to 20 carbons, or aralkyl groups having from 7 to 20 carbons, provided that at least two R1 in a molecule are the alkenyl groups; R2 is an aryl group having from 6 to 20 carbons or an aralkyl group having from 7 to 20 carbons; R3 is an alkyl group having from 1 to 12 carbons; and a, b, c, and d are respectively numbers satisfying: 0.01≦a≦0.5, 0≦b≦0.7, 0.01≦c