NOVELTY - A secondary battery comprises cathode (21), anode (22), and non-aqueous electrolytic solution containing cyclic ether compound including skeleton and greater than or equal to 1 substituents introduced into skeleton in which skeleton contains greater than or equal to 1 greater than or equal to 4-membered oxygen-containing rings.    USE - A secondary battery for battery pack, electric vehicle, electric power storage system, electric power tool, and electronic apparatus (all claimed).    ADVANTAGE - Superior battery characteristics can be achieved.    DETAILED DESCRIPTION - A secondary battery comprises cathode (21), anode (22), and non-aqueous electrolytic solution containing cyclic ether compound including skeleton and greater than or equal to 1 substituents introduced into skeleton in which skeleton contains greater than or equal to 1 greater than or equal to 4-membered oxygen-containing rings and each substituent is monovalent group represented by formula -X-O-R (1).    X=divalent chain saturated hydrocarbon or halide; and    R=monovalent chain saturated hydrocarbon, monovalent chain unsaturated hydrocarbon, monovalent (cyclic) saturated hydrocarbon, monovalent (cyclic) unsaturated hydrocarbon, monovalent O-containing (cyclic) saturated hydrocarbon group, monovalent O-containing (cyclic) unsaturated hydrocarbon, halide, monovalent group obtained by bonding greater than or equal to 2 hydrocarbons, or H, provided that greater than or equal to 1 of R groups contain -C=C- or -CC- bond which is bonded to ether bond -O-.    INDEPENDENT CLAIMS are included for:    (1) non-aqueous electrolytic solution comprising cyclic ether compound including skeleton and greater than or equal to 1 substituents introduced into skeleton in which skeleton contains greater than or equal to 1 greater than or equal to 4-membered oxygen-containing rings and each substituent is monovalent group represented by formula -X-O-R (1);    (2) battery pack comprising secondary battery, control section configured to control operation of secondary battery, and switch section configured to switch operation of secondary battery according to instruction of control section;    (3) electric vehicle comprising secondary battery, conversion section configured to convert electric power supplied from secondary battery into drive power, drive section configured to operate according to drive power, and control section configured to control operation of secondary battery;    (4) electric power storage system comprising secondary battery, greater than or equal to 1 electric devices configured to be supplied with electric power from secondary battery, and control section configured to control supplying of electric power from secondary battery to greater than or equal to 1 electric devices;    (5) electric power tool comprising secondary battery and movable section configured to be supplied with electric power from secondary battery; and    (6) electronic apparatus comprising secondary battery as electric power supply source.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a secondary battery.    Battery can (11)    Electrode body (20)    Cathode (21)    Anode (22)    Separator (23)