CATALYTIC INK ADJUSTMENT METHOD

A catalytic ink preparation method of the present invention includes the steps of: mixing a first ion conductor and a catalyst thereby to prepare a first ink; and concentrating the first ink. The method further includes the step of adding a second ion conductor to the concentrated first ink. With sash a catalytic ink preparation method, the quantity of solvent in the first ion conductor is reduced by concentrating. Specifically, the first ion conductor adheres to the catalyst, and re-dissolution is not prone to occur with the first ion conductor when the second ion conductor is added. Thus, it is possible to efficiently manufacture the electrode catalyst in which a significant part of the surface of the catalyst is covered with two ionomer layers and there is little portion covered with only one ionomer layer.