Cross hole deburring tool, cross hole deburring method, and rotary valve machined by using the same

A cross hole deburring tool which performs rotary cutting on a cross hole burr occurring on a cross ridgeline part between a through path and an inner circumferential surface of a spherically-shaped hollow part, with a center axis of the through path in a cylindrical shape not passing through a spherical center of the spherically-shaped hollow part in a workpiece and with the through path drilled into the spherically-shaped hollow part toward a direction passing through a diameter of the spherically-shaped hollow part, wherein a tool main body of this tool includes a tip part and a shank, the tip part has a shape obtained by setting a diameter axis of a circle, setting an eccentric axis parallel to the diameter axis and away therefrom by a predetermined eccentric distance, setting a closed region in a bow shape formed of a line segment obtained by cutting the eccentric axis by the circle and a minor arc on the circle by defining this line segment as a chord, setting an outer surface shape of a bow-shaped solid of revolution formed by rotating this bow shape about the eccentric axis, and taking this outer surface shape as the shape of the tip part, the tip part is configured to have an outer shape adapted to a width across corners of the cross ridgeline part, the eccentric distance is set so that a diagonal deburring width of a machined surface obtained by deburring is substantially uniform, and a surface width of the machined surface can be finished so as to be a substantially uniform width over an entire periphery.