This composition contains (A) 100 parts of an organopolysiloxane having two groups represented by general formula (1) (R1 represents a monovalent hydrocarbon group having 1-20 carbon atoms, R2 represents an oxygen atom or the like, R3 represents an acryloyloxyalkyl group or the like, p represents a number satisfying 0≤p≤10, and “a” represents a number satisfying 1≤a≤3) per molecule, (B) 1-500 parts of a monofunctional (meth)acrylate compound not containing a siloxane structure, (C) 1-5,000 parts of an organopolysiloxane resin containing (a) an R43SiO1/2 unit (in the formula, R4 represents a monovalent hydrocarbon group having 1-10 carbon atoms) and (b) a SiO4/2 unit, where the molar ratio of the unit (a) to the unit (b) is in the range of 0.6 to 1.2:1, (D) 1-100 parts of fine powder silica, and (E) 0.01-20 parts of an optical polymerization initiator. The compound has good shape retention properties and curability for irradiation with ultraviolet light, and provides a cured product which has excellent adhesion suitable for a temporary fixing material.