The present invention provides a copolymer used as oily gelling agent with which a stable oily gelled composition can be prepared. The copolymer of the present invention is characterized by comprising a hydrophobic monomer represented by the following general formula (1) and a hydrophilic monomer represented by the following general formula (2) and/or the following general formula (3). (In formula (1), R 1 is a straight-chain or branched-chain alkyl group having 16 to 22 carbon atoms. R 2 is a hydrogen atom or a methyl group.) (In formula (2), R 3 is a hydrogen atom, a glyceryl group, a straight-chain or branched-chain hydroxyalkyl group having 1 to 4 carbon atoms, or a polypropylene glycol group represented by -(C 3 H 6 O) n H (here, n is an integer of 2 to 10). R 4 is a hydrogen atom or a methyl group.) (In formula (3), R 5 is a hydrogen atom or a methyl group, R 6 is a straight-chain or branched-chain alkyl group or hydroxyalkyl group having 1 to 4 carbon atoms, or a substituent represented by the following structural formula (4).)
