An organic electroluminescent compound represented by the following formula 1: wherein X 1 to X 3 each independently represent CH or N, with a proviso that at least one of X 1 to X 3 are N; Ar 1 and Ar 2 each independently represent a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (5- to 30-membered)heteroaryl; Ar 3 each independently represents hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (5- to 30-membered)heteroaryl, a substituted or unsubstituted (3- to 7-membered)heterocycloalkyl, or a substituted or unsubstituted (C3-C30)cycloalkyl; Ar 4 each independently represents hydrogen, phenyl, naphthyl, biphenyl or pyridyl; L 1 represents a single bond, a substituted or unsubstituted (C6-C30)arylene, or a substituted or unsubstituted (5- to 30-membered)heteroarylene; R 1 and R 2 each independently represent a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (5- to 30-membered)heteroaryl; or are linked to each other to form a substituted or unsubstituted, mono- or polycyclic, (C3-C30) alicyclic, aromatic ring, or a combination thereof, whose carbon atom(s) may be replaced with at least one heteroatom selected from nitrogen, oxygen, and sulfur; a represents an integer of 1 to 5, and b represents an integer of 1 to 4, in which if a and b represent an integer of 2 or more, each Ar 3 and each Ar 4 may be the same or different; and the heteroaryl(ene) and the heterocycloalkyl contain at least one heteroatom selected from B, N, O, S, Si, and P. X 1 to X 3 each independently represent CH or N, with a proviso that at least one of X 1 to X 3 are N; Ar 1 and Ar 2 each independently represent a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (5- to 30-membered)heteroaryl; Ar 3 each independently represents hydrogen, deuterium, a halogen, a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, a substituted or unsubstituted (5- to 30-membered)heteroaryl, a substituted or unsubstituted (3- to 7-membered)heterocycloalkyl, or a substituted or unsubstituted (C3-C30)cycloalkyl; Ar 4 each independently represents hydrogen, phenyl, naphthyl, biphenyl or pyridyl; L 1 represents a single bond, a substituted or unsubstituted (C6-C30)arylene, or a substituted or unsubstituted (5- to 30-membered)heteroarylene; R 1 and R 2 each independently represent a substituted or unsubstituted (C1-C30)alkyl, a substituted or unsubstituted (C6-C30)aryl, or a substituted or unsubstituted (5- to 30-membered)heteroaryl; or are linked to each other to form a substituted or unsubstituted, mono- or polycyclic, (C3-C30) alicyclic, aromatic ring, or a combination thereof, whose carbon atom(s) may be replaced with at least one heteroatom selected from nitrogen, oxygen, and sulfur; a represents an integer of 1 to 5, and b represents an integer of 1 to 4, in which if a and b represent an integer of 2 or more, each Ar 3 and each Ar 4 may be the same or different; and the heteroaryl(ene) and the heterocycloalkyl contain at least one heteroatom selected from B, N, O, S, Si, and P. <EOS>