To deposit a zinc oxide film having good film characteristics stably over a long period by an electrolytic solution in which the individual control of the concentration of zinc ions and nitric ions in the electrolytic solution is possible, and the accumulation of impurity ions is extremely little.

An electrically conductive substrate 106 dipped into an electrolytic solution 103 at least containing nitric ions and zinc ions is used as the cathode, and an electrode 107 dipped into the electrolytic solution 103 is used as the anode, and energizing is performed thereto, so that a zinc oxide film is deposited on the electrically conductive substrate 106. In this case, a solution in which the concentration of zinc ions has been controlled by an electrodialysis method is fed into the electrolytic solution 103.