PURPOSE: To obtain a lubricant ensuring high reserving stability and consistency of lubricating action, by blending a lubricant, a particular dipheylamine compound of a phenothiazine, and a specified organic compound.

CONSTITUTION: The blend comprises (A) a lubricant, (B) at least one component selected from the group consisting of a diphenylamine such as 1 to 5 wt.% diphenylamine, N-substituted diphenylamine compound represented by formula I (wherein R' is methyl, ethyl, propyl, an aryl), a diphenylamine compound such as diphenylamine compound represented by formula II, a phenothiazine represented by formula III, 3,7-di-tert-octyl phenothiazine represented by formula IV, and (C) at least one kind of compound represented by formula V (wherein R1 and R2 are each a 3-9C alkyl, 5-10C cycloalkyl, pinane-10-yl; Q is -S-, -S-CH2-S-, -S-CH2-CH2-S-), wherein components (B) and (C) are present in a weight ratio of (B):(C) of 1:0.6 to 1:6.