Abstract: The base structure of a bowling pin having an aperture at the center of the base portion thereof for the engagement with the bottom portion of the core of the bowling pin, characterized in that an inner wall is circumferentially provided around the aperture and an outer wall is provided concentrically adjacent to the inner wall, and a circular slot is formed by the inner wall and the outer wall; the outer surface of the outer wall is provided with a plurality of screw threads and at least a pair of transverse hole are provided perpendicular to the circular slot so that the outer surface of the outer wall communicates with the circular slot, whereby a resin solution covers the plurality of the screw threads and flows into the slot, and forms a compact base structure.