A non-oil repellent photosensitive material layer 2 and an oil repellent photosensitive material layer 3 formed by coating on a substrate 1 are exposed at the same time with light having a single wavelength (I-line) in accordance with bank regions and thereafter developed. In consequence, banks 300 are formed having a double-layer structure which is comprised of bottom layer portions 31 of a non-oil repellent material and top layer portions 32 of an oil repellent material. This blocks organic EL materials supplied between the banks 300 from moving beyond tops of the banks 300 and prevents color mixing of the organic EL materials. Further, since the bottom layer portions 31 between which organic layers are formed are made of the non-oil repellent material, the profiles of the organic layers will not change due to surface tension.