PURPOSE: To provide a lubricating oil compsn. which has excellent low-temperature flow characteristics and lubricating properties and gives little damage to sealing materials, by blending a polyether compd. having a specified structure with a synthetic lubricating oil other than polyether compd. in a specified ratio.

CONSTITUTION: A lubricating oil compsn. contains a polyether compd. (A) of formula I or II (wherein R1 is a residue of a 6W20C branched alcohol having a solidifying point of 0°C or below; R2 is H, a 1W28C hydrocarbon group; A is 3 or 4C alkylene; n is 3W40) and a synthetic lubricating oil (B) (e.g. a 4W16C α-olefin oligomer) other than polyether which is dissolved in component A at -20°C to form a clear soln. in a weight ratio of A to B of 1:1W1:19. By combining components A and B in a specified ratio, a compsn, can be obtd. which has excellent low-temperature flow characteristics, low-temperature stability and lubricating properties, gives little damage to sealing materials, has excellent compatibility with additives and can be widly used at low temp.