PROBLEM TO BE SOLVED: To provide a fine hollow protrusion having an opening, which can reduce pain when puncturing the skin and is hard to break. SOLUTION: A fine hollow projection tool 1 having an opening portion 3h on the tip side and having an internal space formed in an internal space connected to the opening portion 3h is projected from a base member 2. When looking at any vertical cross section passing through the apex of the hollow protrusion 3, the wall thickness T1 at the apex side portion TB on the apex side is the wall thickness at the lower portion BP on the base member 2 side of the apex side portion TB. It is thinner than T2, and the distance M1c between the inner walls 31 and 31 in the apex side portion TB is smaller than the distance M2c between the inner walls 31 and 31 in the lower side portion BP. The root portion 34 of the fine hollow protrusion 3 protruding from the base member 2 has a curvature, and enters the fine hollow protrusion 3 on the back surface 25 opposite to the protruding front surface 24 of the fine hollow protrusion 3 in the base member 2. The entrance portion 23 of the above has a curvature. [Selection diagram] Fig. 3【課題】皮膚に穿刺する際に痛みが低減できると共に折れ難い、開孔を有する微細中空突起具を提供すること。【解決手段】先端側に開孔部３ｈを有し、内部に開孔部３ｈに繋がる内部空間の形成された微細中空突起部３が、基底部材２から突出する微細中空突起具１は、微細中空突起部３の頂点を通る何れかの縦断面を視た際に、頂点側の頂点側部位ＴＢにおける肉厚Ｔ１が、頂点側部位ＴＢよりも基底部材２側の下方側部位ＢＰにおける肉厚Ｔ２よりも薄く、頂点側部位ＴＢにおける内壁３１，３１同士の間隔Ｍ１ｃが下方側部位ＢＰにおける内壁３１，３１同士の間隔Ｍ２ｃよりも小さい。基底部材２から突出する微細中空突起部３の根本部３４が曲率を有し、基底部材２における微細中空突起部３の突出する表面２４とは反対側の裏面２５の微細中空突起部３内への入口部２３が曲率を有している。【選択図】図３
