The working fluid for traction drive as claimed in claim 1 in which the alkane compound as the component (A-4) is a compound represented by the general formula ##STR35## in which R4, R5, 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.