A carbazole derivative represented by the following Chemical Formula 1: wherein, in Chemical Formula 1, L is a substituted or unsubstituted arylene group; or a substituted or unsubstituted divalent heterocyclic group; L1 and L4 are the same as or different from each other, and each independently a direct bond; a substituted or unsubstituted arylene group; or a substituted or unsubstituted divalent heterocyclic group; L2 and L3 are the same as or different from each other, and each independently a direct bond; a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms; a substituted or unsubstituted alkenylene group having 1 to 30 carbon atoms; a substituted or unsubstituted arylene group having 6 to 30 carbon atoms; or a substituted or unsubstituted divalent heterocyclic group having 2 to 30 carbon atoms and comprising one or more atoms selected from the group consisting of O, Se and S; L5 and L6 are the same as or different from each other, and each independently a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms; a substituted or unsubstituted alkenylene group having 2 to 30 carbon atoms; a substituted or unsubstituted arylene group having 6 to 30 carbon atoms; or a substituted or unsubstituted divalent heterocyclic group having 2 to 30 carbon atoms; a and b are each an integer of 1 to 6; when a and b are each 2 or greater, structures in the parentheses are the same as or different from each other; R1 and R2 are the same as or different from each other, and each independently hydrogen; deuterium; a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms; a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms; a substituted or unsubstituted aryl group having 6 to 30 carbon atoms; a substituted or unsubstituted arylamine group; or a substituted or unsubstituted heterocyclic group having 2 to 30 carbon atoms, or adjacent substituents bond to each other to form a substituted or unsubstituted hydrocarbon ring; or a substituted or unsubstituted heterocyclic group; n is an integer of 1 to 4; when n is an integer of 2 or greater, two or more Ls are the same as or different from each other; and Y1 to Y6 are the same as or different from each other, and each independently hydrogen; or a functional group capable of crosslinking by heat or light, and at least one or more of Y1 to Y4 are a functional group capable of crosslinking by heat or light, wherein the term "substituted or unsubstituted" means being substituted with one or more substituents selected from the group consisting of deuterium; a halogen group; a nitrile group; a nitro group; a hydroxyl group; an alkyl group; an alkoxy group; an alkenyl group; an aryl group; and a heterocyclic group, or being unsubstituted, wherein functional group capable of crosslinking by heat or light is any one of the following structures: L is a substituted or unsubstituted arylene group; or a substituted or unsubstituted divalent heterocyclic group; L1 and L4 are the same as or different from each other, and each independently a direct bond; a substituted or unsubstituted arylene group; or a substituted or unsubstituted divalent heterocyclic group; L2 and L3 are the same as or different from each other, and each independently a direct bond; a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms; a substituted or unsubstituted alkenylene group having 1 to 30 carbon atoms; a substituted or unsubstituted arylene group having 6 to 30 carbon atoms; or a substituted or unsubstituted divalent heterocyclic group having 2 to 30 carbon atoms and comprising one or more atoms selected from the group consisting of O, Se and S; L5 and L6 are the same as or different from each other, and each independently a substituted or unsubstituted alkylene group having 1 to 30 carbon atoms; a substituted or unsubstituted alkenylene group having 2 to 30 carbon atoms; a substituted or unsubstituted arylene group having 6 to 30 carbon atoms; or a substituted or unsubstituted divalent heterocyclic group having 2 to 30 carbon atoms; a and b are each an integer of 1 to 6; when a and b are each 2 or greater, structures in the parentheses are the same as or different from each other; R1 and R2 are the same as or different from each other, and each independently hydrogen; deuterium; a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms; a substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms; a substituted or unsubstituted aryl group having 6 to 30 carbon atoms; a substituted or unsubstituted arylamine group; or a substituted or unsubstituted heterocyclic group having 2 to 30 carbon atoms, or adjacent substituents bond to each other to form a substituted or unsubstituted hydrocarbon ring; or a substituted or unsubstituted heterocyclic group; n is an integer of 1 to 4; when n is an integer of 2 or greater, two or more Ls are the same as or different from each other; and Y1 to Y6 are the same as or different from each other, and each independently hydrogen; or a functional group capable of crosslinking by heat or light, and at least one or more of Y1 to Y4 are a functional group capable of crosslinking by heat or light, wherein the term "substituted or unsubstituted" means being substituted with one or more substituents selected from the group consisting of deuterium; a halogen group; a nitrile group; a nitro group; a hydroxyl group; an alkyl group; an alkoxy group; an alkenyl group; an aryl group; and a heterocyclic group, or being unsubstituted, wherein functional group capable of crosslinking by heat or light is any one of the following structures: