To provide a ridge ventilator which is simple in structure, low in cost, and effective at flashing, and to provide component parts of the ridge ventilator.

The ridge ventilator is provide for a roof which has a ridge beam having top ridge tiles fixed thereto; sheathing boards inclined rightward and leftward across an opening lower stage at a bottom thereof; and pantiles arranged on upper surfaces of the sheathing boards while securing an interval away from the same, and inclined rightward and leftward across an opening upper stage wider than the opening lower stage. The ridge ventilator is formed of: () a ridge support member which is secured to tops of the sheathing boards, protruded from the opening upper stage, and intermittently supports the ridge beam; () watertightness ensuring members which are each formed, in cross section, of a vertical surface and an inclined surface connected together at an obtuse angle, and small seams protruded outward from an upper edge of the vertical surface and protruded inward from a lower edge of the inclined surface; and () gutter members which are each formed, in cross section, of a short vertical surface connected to a lower edge of an inclined bottom surface, a long vertical surface connected to an upper edge of the inclined bottom surface, and small seams protruded from upper edges of the long and short vertical surfaces in a manner facing to each other. Herein () the vertical surface of the watertightness retaining member is intermittently secured to a longitudinal side of each side surface of the ridge beam via packings, and sealing materials in a compressed state are intermittently interposed in a gap with respect to a pantile upper surface. Further () the gutter member is secured to the tops of the sheathing boards, the short vertical surface abuts on a pantile lower surface, and the long vertical surface is protruded from the opening upper stage.