In an organic EL device having a first electrode of a light reflective material, organic layer including an organic light emitting layer, semitransparent reflection layer, and second electrode of a transparent material that are stacked sequentially, and so configured that the organic layer functions as a cavity portion of a cavity structure, light that resonates in a certain spectral width (wavelength .lamda.) is extracted by so configuring that optical path length L becomes minimum in a range satisfying (2L)/.lamda.+.PHI.((2.pi.)=m (m is an integer) where the phase shift produced in light generated in the organic light emitting layer when reflected by opposite ends of the cavity portion is .PHI. radians, L is optical path length of the cavity portion, and .lamda. is the peak wavelength of the spectrum of part of light to be extracted.