The present invention relates to a copolymer having a specified carbosiloxane dendrimer structure and a long-chain alkyl group with 14 to 22 carbon atoms in a specified ratio, and a cosmetic comprising the copolymer as a cosmetic raw material. The cosmetic raw material has good miscibility with other cosmetic raw materials, and therefore, can improve stability of the formulation in a cosmetic, as well as can provide good water resistance, sebum resistance, glossiness, tactile sensation and/or adhesive properties to the hair and/or skin to a cosmetic, and also provide a cosmetic formed by blending the aforementioned cosmetic raw material, which exhibits superior surface protective properties, outer appearance and/or sensation during use.