Wherein the syringe cap includes a convex portion extending in the circumferential direction of the cap body, the convex portion has a top portion located on the outer side in the radial direction of the cap body from the outer peripheral surface of the cap main body, A first inclined surface having a starting end at the top portion and having a terminating end on an outer peripheral surface of the cap main body which is closer to the base end side of the cap main body than the starting end, And a second inclined surface having an end on an outer peripheral surface of the cap main body, wherein a shortest distance from the starting end to the terminal end of the first inclined surface is shorter than a shortest distance from the starting end of the second inclined surface to the end Shorter than distance.シリンジキャップは、キャップ本体の周方向に延びる凸部を含み、前記凸部は、前記キャップ本体の外周面よりも該キャップ本体の径方向外方に位置する頂部と、前記頂部に始端を有するとともに、始端よりも前記キャップ本体の基端側にある前記キャップ本体の外周面上に終端を有する第一傾斜面と、前記頂部に始端を有するとともに、始端よりも前記キャップ本体の先端側にある前記キャップ本体の外周面上に終端を有する第二傾斜面と、を含み、前記第一傾斜面の前記始端から前記終端までの最短距離は、前記第二傾斜面の前記始端から前記終端までの最短距離よりも短い。
