PROBLEM TO BE SOLVED: To provide a nest building prevention tool for surely preventing nest building.SOLUTION: A nest building prevention tool 100 comprises: a movable body 110 comprising a spherical body and a shank whose one end is fixed to the spherical body and which is formed into a rod-state； a slip guiding part 120 which is coupled to another end of the shank on the movable body 110 and has a contour formed into a conical shape or hemispherical shape whose diameter becomes smaller as separates from the spherical body； a support part 130 for supporting the spherical body so as to roll by coming into contact with an outer surface of the spherical body on the movable body 110 from a plurality of directions； and a fitting part coupled to the support part 130 and having a female screw for receiving screwing of a male screw. The movable part 110 has a mass center in a state in which the slip guiding part 120 is coupled, the mass center being located on an opposite side to a fitting position of the shank on the spherical body.SELECTED DRAWING: Figure 7COPYRIGHT: (C)2020,JPO&INPIT【課題】営巣を確実に防止すること。【解決手段】球体と、一端が当該球体に固定された棒形状をなす軸体とを備えた可動部１１０と、可動部１１０における軸体の他端に連結され、球体から離間するほど径が小さくなる錐形状または半球形状の外形をなす滑落誘導部１２０と、可動部１１０における球体の外表面に複数方向から接触することにより球体を転動可能に支持する支持部１３０と、支持部１３０に連結され、雄ネジの螺合を受け付ける雌ネジを備えた取付部と、を備え、可動部１１０が、滑落誘導部１２０が連結された状態における質量中心を、球体における軸体の固定位置とは反対側に備えた営巣防止器１００を構成した。【選択図】図７
