The present invention provides an organic light emitting device comprising a first electrode, a second electrode, and at least two organic material layers interposed therebetween, including a light emitting layer, wherein the organic material layers comprise at least one layer of a hole injecting layer, a hole transporting layer and a hole injecting and transporting layer, and at least one of the hole injecting layer, the hole transporting layer and the hole injecting and transporting layer comprises a material with a HOMO energy level of -4 eV or less, and a material with a LUMO energy level of -4 eV or less, and a process for preparing the same.