To provide a method for manufacturing a high-definition relief printing plate excellent in print wear by which an amount of an eluted material from the resin relief printing plate that shortens the life time of an organic electronic device is decreased by an easy means, and to provide a method for manufacturing an organic electronic device by using the relief printing plate.

The method for manufacturing the relief printing plate includes: a step of forming a relief printing plate by exposing a photosensitive resin layer through a photomask to form a relief pattern and developing; a second exposure step of exposing the whole relief printing plate by using a light source that has at least one emission line spectrum in each wavelength region of from 200 to 300 nm, from 300 to 400 nm and from 400 to 450 nm; and a step of cleaning the relief printing plate by the use of an organic solvent.