A polycarbonate copolymer comprising: a repeating unit represented by a formula below; and a molar copolymer composition represented by Ar 2 /(Ar 1 +Ar 2) in a range of 25 mol% to 50 mol%, where: Ar 1 is a substituted or unsubstituted naphthylene group, or a group having a structure represented by a formula below; Ar 2 is a substituted or unsubstituted naphthylene group, or a group having a structure represented by a formula below; a chain end is terminated by a monovalent aromatic group or a monovalent fluorine-containing aliphatic group; and n represents an average repeating number of an Ar 1 block and is a numeral of 1.0 to 3.0; provided that Ar 1 and Ar 2 are not the same; wherein: R 1 and R 2 each represent a hydrogen atom, a halogen atom, a trifluoromethyl group, an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms and a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms; R 1 and R 2 are allowed to be a plurality of groups for a single aromatic ring, in which the plurality of groups are allowed to be the same or different; and X represents a single bond, -O-, -CO-, -S-, -SO-, -SO 2 - -CR 3 R 4 - (in which R 3 and R 4 each independently are a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a trifluoromethyl group or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms), a substituted or unsubstituted cycloalkylidene group having 5 to 20 carbon atoms, a substituted or unsubstituted bicyclo- or tricyclo-hydrocarbon-diyl group having 5 to 20 carbon atoms, a substituted or unsubstituted α, ω-alkylene group having 2 to 12 carbon atoms, a substituted or unsubstituted 9,9-fluorenylidene group, a 1,8-menthanediyl group, a 2,8-menthanediyl group, a substituted or unsubstituted arylene group having 6 to 12 carbon atoms and a divalent group represented by a formula below, wherein: R 5 to R 7 each represent the same groups for R 1 and R 2, or a group selected from an alkylidene arylene alkylidene group having 8 to 16 carbon atoms represented by a formula below, and whereby R 8 to R 11 each represent the same groups as defined for R 1 and R 2. Ar 1 is a substituted or unsubstituted naphthylene group, or a group having a structure represented by a formula below; Ar 2 is a substituted or unsubstituted naphthylene group, or a group having a structure represented by a formula below; a chain end is terminated by a monovalent aromatic group or a monovalent fluorine-containing aliphatic group; and n represents an average repeating number of an Ar 1 block and is a numeral of 1.0 to 3.0; R 1 and R 2 each represent a hydrogen atom, a halogen atom, a trifluoromethyl group, an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms and a substituted or unsubstituted aryloxy group having 6 to 12 carbon atoms; R 1 and R 2 are allowed to be a plurality of groups for a single aromatic ring, in which the plurality of groups are allowed to be the same or different; and X represents a single bond, -O-, -CO-, -S-, -SO-, -SO 2 - -CR 3 R 4 - (in which R 3 and R 4 each independently are a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a trifluoromethyl group or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms), a substituted or unsubstituted cycloalkylidene group having 5 to 20 carbon atoms, a substituted or unsubstituted bicyclo- or tricyclo-hydrocarbon-diyl group having 5 to 20 carbon atoms, a substituted or unsubstituted α, ω-alkylene group having 2 to 12 carbon atoms, a substituted or unsubstituted 9,9-fluorenylidene group, a 1,8-menthanediyl group, a 2,8-menthanediyl group, a substituted or unsubstituted arylene group having 6 to 12 carbon atoms and a divalent group represented by a formula below, R 5 to R 7 each represent the same groups for R 1 and R 2, or a group selected from an alkylidene arylene alkylidene group having 8 to 16 carbon atoms represented by a formula below, and