. "The working fluid for traction drive as claimed in claim 1 in which the cyclohexyl decahydronaphthalene compound as the component (A-5) is a compound represented ty the general formula ##STR36## in which R6 and R7 are each a hydrogen atom or a methyl group, R8 is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms and the subscripts l, m and n are each a positive integer of 1, 2 or 3." . . . .