The present invention is related to an intermediate layer of an organic electroluminescent device comprising an amine derivative substance which may further comprise a functional group capable of forming crosslinks. In particular, the substance may have excellent solubility and can be easily formed into a thin film. Specifically, the thin film may be stable in the solvent and can be easily formed to various thicknesses. Furthermore, the band gaps and LUMO/HOMO values may be easily controlled depending of the characteristics of the hole transporting material, so that an intermediate layer with the desired characteristics may be formed. Accordingly, the introduction of an intermediate layer manufactured using the substance of the present invention as the intermediate layer may result in an organic electroluminescent device having high efficiency and a longer lifespan.