PURPOSE: To obtain an oil additive composition reduced in haze and improved in storage life by adding a hydrocarbyl substituted succinic acid into a composition containing a viscosity index improving agent composed of a lubricating oil, an ethylene-α-olefin copolymer, etc.

CONSTITUTION: This composition is prepared by adding (B) a hydrocarbyl substituted succinic acid into a composition containing (A) (i) a lubricating oil, (ii) an ethylene-α-olefin copolymer of 2 or less Mw/Mn ratio and/or 1.8 or less Mz/Mw ratio in which crystalline segments constitute approximately 10 wt.% of copolymer chains and contains 57% or more of ethylene, and low crystalinity segments contain 53% or less of ethylene, and (iii) an oil-insoluble haze forming substance produced from the production or finishing process of the component (ii).