Abstract: The present invention addresses the problem of providing a lubricating oil composition having excellent heat resistance (suppression of discoloration in heating) and tackiness while maintaining excellent viscosity properties of a lubricating oil composition using a ricinolic acid polymer. The present invention provides a copolymer (B) containing structural units (a) derived from ricinolic acid, structural units (b) derived from an aliphatic dicarboxylic acid and structural units (c) derived from a diol having 2 to 10 carbon atoms in a specific ratio and having a specific intrinsic viscosity, and provides a lubricating oil composition containing a base oil and the copolymer (B) and having a mass ratio (mass of (A) /mass of (B)) of the base oil (A) to the copolymer (B) of 60/40 to 99.5/0.5.