a method of producing an ink - jet head having an ink chamber composed of at least a first wall member and a second wall member , wherein the first wall member includes a vibrating wall made of a piezoelectric ceramic on which an electrode layer is formed and the second wall member forms a fixed wall , comprising steps of : combining the first wall member and the second wall member into one body so that the ink chamber is formed between the first wall member and the second wall member and the electrode layer is located inside the ink chamber ; and subjecting the combined one body of the first wall member and the second wall member to gas phase polymerization so that a resin layer of poly - para xylylene or its derivative is formed on the electrode layer in the ink chamber .