Traction drive fluid

There is disclosed a traction drive fluid which comprises a base oil blended with (A) an active phosphate ester base compound, (B) a boron-containing imide base dispersant (e.g. polyalkenyl succinimide treated with a boron compound ) and (C) a boron-free imide base dispersant (e.g. polyalkenyl succinimide) in such blending amounts that the phosphorus content derived from the component (A) and the boron content derived from the component (B) are each 100 to 600 ppm, preferably 60 to 300 ppm by weight, and at least 60 ppm by weight, respectively based on the base oil, and the boron-free imide base dispersant (C) is blended so that the ratio by weight of the nitrogen in the component (C) to the boron in the component (B) is at least 1, preferably 1 to 6. The traction drive fluid has excellent wear resistance and excellent scoring resistance of a steel material element, is capable of suppressing surface damage such as peeling of a friction material and in particular, is well suited for use as a lubricating oil for a traction drive continuous variable transmission used in an automobile.