The present invention relates to a manufacturing method which uses an ink jet method for forming various kinds of thin films in an electronic device such as an organic EL panel or an organic thin film transistor and ink suitably used in the method. The manufacturing method manufactures an electronic device such as an organic layer which forms a pixel portion of a hole injection layer or the like of an organic EL panel or an active layer of an organic thin film transistor using ink composition which is formed by adding tertiary-alcohol into ink which uses water as a main solvent. As the tertiary-alcohol, 3-methyl-1-butyn-3-ol may be used. An addition quantity of alcohol with respect to ink is set to a value which falls within a range from approximately 25wt % to 40wt %.