Disclosed is a cage-type copolymer in which a cage structure is incorporated in its main chain. Also disclosed is a curable resin composition comprising the said copolymer. Specifically disclosed is a curable cage-type silicone copolymer with a constituent unit represented by general formula (1) Y—[Z—(O1/2—R22SiO1/2)a—(R1SiO3/2)n—(O1/2)b]—Z—Y: wherein R1 and R2 each is a vinyl group, an alkyl group, a phenyl group, a (meth)acryloyl group, an allyl group, or an oxirane ring-containing group, Z is a divalent group represented by the following general formula (2) wherein R3 is a hydrogen atom, a vinyl group, an alkyl group, a phenyl group, a (meth)acryloyl group, an allyl group, or an oxirane ring-containing group, and Y is any one of the groups represented by the following general formula (3) [(R4O)R22SiO1/2]a—[R12SiO3/2]n—[O1/2]—, general formula (4) [R4O1/2]b—[R1SiO3/2]n—[O1/2—R22SiO1/2]—, general formula (5) (R4O1/2)—, and general formula (6) (R23SiO1/2)— wherein R4 is a hydrogen atom, a methyl group, or an ethyl group.