A non-aqueous electrolytic solution containing a ketone compound having the formula (I): ##STR00001## in which each of R.sup.1 and R.sup.2 is linear or branched alkyl; and each of R.sup.3, R.sup.4, R.sup.5 and R.sup.6 is hydrogen or linear or branched alkyl; however, R.sup.1 and R.sup.4 can be combined to form a cycloalkanone ring in conjunction with a propanone skeleton to which R.sup.1 and R.sup.4 are connected, and two or more of alkyl of R.sup.2, alkyl of R.sup.5, a branched chain of alkyl of R.sup.1, and a branched chain of alkyl of R.sup.4 can be combined to form a cycloalkane ring, or alkyl of R.sup.1 and alkyl of R.sup.2 and/or alkyl of R.sup.4 and alkyl of R.sup.5 can be combined to each other to form a cycloalkane ring, is favorably employed for manufacturing a lithium secondary battery that is excellent in the battery performances and cycle performance.