To obtain a curable organopolysiloxane compsn. which is cured by the exposure to a high-energy ray and then to moisture and is used for bonding a substrate to an adhered by compounding a specific silicon resin, an organopolysiloxane, an organosilane, and a condensation catalyst.

An organopolysiloxane compsn. having a viscosity of 30,000P or lower at 25°C is obtd. by compounding 100 pts.wt. compsn. comprising 30-75wt.% silicone resin represented by the mean unit formula: R1aSiO(4-a)/2 (wherein R1 is a monovalent hydrocarbon group or alkoxy; and a is 0.75-2.5) and 70-25wt.% organopolysiloxane having a viscosity of 1-1,000P at 25°C and having mercaptized siloxy groups represented by the formula (wherein R2 is a 1-10C alkylene; R3 is an alkoxy; R4 is an alkyl; and (x) is 1 or 2), 0.1-10 pts.wt. mercaptized organosilane represented by the general formula: (HSR5)R6ySiR7(3-y) (wherein R5 is the same as R2; R6 is the same as R3; R7 is the same as R4; and (y) is 1-3), and 0.01-10 pts.wt. condensation catalyst.