Abstract: Disclosed is a polyorganosiloxane composition containing the following components (a)-(c). (a) 100 parts by mass of a polyorganosiloxane obtained by mixing at least one silanol compound represented by the general formula (1) below, at least one alkoxysilane compound represented by the general formula (2) below, and at least one catalyst selected from the group consisting of compounds represented by the general formula (3) below, compounds represented by the general formula (4) below and Ba(OH)2, and polymerizing the mixture without actively adding water thereinto [chemical formula 1] R2Si(OH)2 (1) [chemical formula 2] R?Si(OR?)3 (2) (chemical formula 3] M(OR??)4 (3) [chemical formula 4] M?(OR??)3 (4) (b) 0.1-20 parts by mass of a photopolymerization initiator (c) 1-100 parts by mass of a compound other than the component (a) having two or more photopolymerizable unsaturated bonding groups.