Provided is a board for ion generation that is capable of generating
negative ions with much better efficiency and in an amount larger than
that of positive ions. In the board for ion generation, a discharge
electrode is formed on one principal surface of a substrate formed of
ceramics, an induction electrode is formed on another principal surface
of the substrate, the discharge electrode and the induction electrode
being disposed opposite to each other, a first protective layer and a
second protective layer are formed so as to cover the discharge electrode
and the induction electrode, respectively. Surface discharge is generated
on a surface of the first protective layer by applying an AC voltage
between the discharge electrode and induction electrode, and positive
ions and negative ions are alternately generated in the air. In the board
for ion generation, the porosity of the substrate is 5 to 10 vol. %.