Purification of hole transporting material by means of ultrafiltration and ion exchange chromatography

In an organic EL device, when a voltage is applied across an anode and a cathode, holes are moved in a hole transport layer and electrons are moved in an electron transport layer, and the holes and the electrons are recombined in a light emitting layer. In the light emitting layer, excitons are produced by energy released upon the recombination, and the excitons release energy in the form of fluorescence or phosphorescence or emit light when returning to the ground state. The hole transport layer is formed from a hole transport material, in which the amount of nonionic impurities having a molecular weight of 5,000 or less, or the amounts of anionic impurities, cationic impurities and nonionic impurities having a molecular weight of 5,000 or less is or are adjusted to be small, so that the decrease of light-emission luminance of the organic EL device is suppressed.