A traction drive fluid composition which comprises component (A) a base oil for traction drives bearing at least one selected from a quaternary carbon atom or an alicyclic structure in the molecule and component (B) at least one polymer having a weight average molecular weight in the range of 8,000 to 40,000 and which is selected from among (a) hydrocarbon polymers each containing as a constituent at least 10 mole % of a monomer bearing a cyclic structure, (b) hydrocarbon polymers each containing at least 25% of quaternary carbon atoms in the backbone chain, and (c) hydrogenated products from the polymers (a) and (b). The traction drive fluid composition is improved in viscosity index without lowering the traction coefficient to a level lower than that of the base oil and is excellent in shear stability.