Lubricating oil additive composition and lubricating oil composition

A lubricating oil additive composition comprising:

• (i) at least one first amide compound, and/or a salt thereof, the at least one first amide compound being a monoamide of at least one C6-30 linear or branched chain saturated or unsaturated monovalent fatty acid (a1), and at least one amine compound (a2), the monoamide having no ester bond, the amine compound (a2) being an alkanolamine oligomer having a structure such that at least one alkanolamine (a3) represented by the following general formula (1) is subjected to dehydration condensation, the alkanolamine oligomer having a degree of polymerization of no less than 2;
• and
• (ii) at least one second amide compound having a structure such that an amino group and at least one hydroxy group of the at least one alkanolamine (a3) represented by the following general formula (1) are acylated with the monovalent fatty acid (a1), the at least one second amide compound being an amide-esterification product, wherein
• a content of the component (ii) is no less than 8.0 mass % based on total content in terms of entire acylated compound obtained by acylating, with the monovalent fatty acid (a1), a compound having an alkanolamine structure where a hydroxy group may be etherified in a state of forming no salt:
• in the general formula (1), n is 1 or 2;
• R1 is C1-4 linear chain alkylene or C3-10 branched chain alkylene having a main chain, the main chain having a carbon number of 2;
• and when n is 2, a plurality of R1's may be the same, and may be different from each other.