PURPOSE: To obtain a rolling oil of oil and water separation type for hot rolling of aluminum which is arbitrarily variable in emulsion concn. and easy of reuse by incorporating a specific compd. such as an alkoxyalkyl ester into mineral oil.

CONSTITUTION: Mineral oil is mixed with 5-100% at least one of an alkoxyalkyl ester of formula I (wherein n is 1 to 3; R1 is 7-22C alkyl; and R2 is 9-21C alkyl), a neopentyl glycol deriv. of formula II or III (wherein n is 1 to 3; and R3 and R4 are each 10-21C alkyl), a trimethylolpropane deriv. of formula IV or V, and a pentaerythritol deriv. of formula VI or VII (wherein n is 1 to 3; and R7 and R8 are each 9-21C alkyl). The resulting rolling oil is injected into water to prepare an aq. emulsion having a concn. of 1 to 20%, which is then fed to a rolling mill through a nozzle to be used.