A ferroelectric element comprising a ferroelectric material containing at least two metals, the ferroelectric element having been produced by a process including a sol-gel process in the presence of a thickener and/or an association preventive from aqueous solutions of respective salts of the metals. The ferroelectric element is advantageous in that the handling of starting compounds and the production of the ferroelectric element are easy, the storage stability of the starting compound solution is good, the cost is low, the ferroelectric element can be formed as a thin layer, particles on the surface of the thin layer are fine and dense, and, hence, the surface smoothness is good. The ferroelectric element is excellent also in piezoelectric properties and therefore can be advantageously used as a piezoelectric element in a piezoelectric ink jet head.