A polymer comprising a unit represented by the following Chemical Formula 1: wherein, in Chemical Formula 1, L1 is a direct bond; a substituted or unsubstituted phenylene group; a substituted or unsubstituted naphthylene group; a substituted or unsubstituted biphenylene group; a substituted or unsubstituted divalent fluorenyl group; or a substituted or unsubstituted divalent carbazolyl group; l1 is an integer of 1 to 10; Ar1 and Ar2 are the same as or different from each other, and each independently a substituted or unsubstituted aryl group; or a substituted or unsubstituted heteroaryl group; R1 to R8 are the same as or different from each other, and each independently hydrogen; deuterium; a halogen group; a hydroxyl group; a cyano group; a substituted or unsubstituted alkyl group; a substituted or unsubstituted cycloalkyl group; a substituted or unsubstituted alkoxy group; a substituted or unsubstituted aryl group; or a substituted or unsubstituted heteroaryl group; r4, r6 and r8 are each independently an integer of 1 to 4; r5 and r7 are each independently an integer of 1 to 3; when r4 is 2 or greater, the two or more R4s are the same as or different from each other; when r5 is 2 or greater, the two or more R5s are the same as or different from each other; when r6 is 2 or greater, the two or more R6s are the same as or different from each other; when r7 is 2 or greater, the two or more R7s are the same as or different from each other; when r8 is 2 or greater, the two or more R8s are the same as or different from each other; when l1 is 2 or greater, the two or more L1s are the same as or different from each other; and n is, as a repetition number of the unit, an integer of 1 to 10,000. L1 is a direct bond; a substituted or unsubstituted phenylene group; a substituted or unsubstituted naphthylene group; a substituted or unsubstituted biphenylene group; a substituted or unsubstituted divalent fluorenyl group; or a substituted or unsubstituted divalent carbazolyl group; l1 is an integer of 1 to 10; Ar1 and Ar2 are the same as or different from each other, and each independently a substituted or unsubstituted aryl group; or a substituted or unsubstituted heteroaryl group; R1 to R8 are the same as or different from each other, and each independently hydrogen; deuterium; a halogen group; a hydroxyl group; a cyano group; a substituted or unsubstituted alkyl group; a substituted or unsubstituted cycloalkyl group; a substituted or unsubstituted alkoxy group; a substituted or unsubstituted aryl group; or a substituted or unsubstituted heteroaryl group; r4, r6 and r8 are each independently an integer of 1 to 4; r5 and r7 are each independently an integer of 1 to 3; when r4 is 2 or greater, the two or more R4s are the same as or different from each other; when r5 is 2 or greater, the two or more R5s are the same as or different from each other; when r6 is 2 or greater, the two or more R6s are the same as or different from each other; when r7 is 2 or greater, the two or more R7s are the same as or different from each other; when r8 is 2 or greater, the two or more R8s are the same as or different from each other; when l1 is 2 or greater, the two or more L1s are the same as or different from each other; and n is, as a repetition number of the unit, an integer of 1 to 10,000.