The present invention relates to an electric discharge machining oil composition and an electric discharge machining method capable of enhancing machining speed in electric discharge machining. This electric discharge machining oil composition is characterized by including (A) a base oil, and (B) one or more types of petroleum resin selected from hydrogenated products of copolymers of dicyclopentadiene and an aromatic compound and having a softening point of 75 to 185° C. and a mean molecular weight (Mn) of 670 to 3000, wherein the kinematic viscosity of the electric discharge machining oil composition at 40° C. is 1 to 10 mm2/s. Further, the electric discharge machining method is characterized by employing said electric discharge machining oil composition, and includes interposing the electric discharge machining oil composition between a workpiece and an electrode, and generating an electric discharge between the workpiece and the electrode in this state to machine the workpiece.