An atomizing electrode includes: a trunk unit made to be tabular-shaped and almost rectangular-shaped for receiving water dropped from water supply means in a direction of gravitational force and delivering the water; and a top end atomizing unit which is a plate-shaped projection formed so as to be projected from a side surface of the trunk unit and formed unitedly with the trunk unit. The trunk unit of the atomizing electrode extends a long-side direction in a horizontal direction, is provided below the cooling unit with a space of a predetermined distance so as not to contact the cooling unit, and is arranged so that when the cooling unit is projected in the direction of gravitational force, a width of the cooling unit in a horizontal direction should be included in a width of a long-side direction of a top surface of the trunk unit exposed to the cooling unit.