PROBLEM TO BE SOLVED: To provide a composition for repairing a hard tissue and a kit for repairing the hard tissue, in which variation of curing time (setting time) due to change of moisture content in the composition is reduced.SOLUTION: There are provided a composition for repairing a hard tissue containing a monomer (A), a polymer powder having volume average particle diameter of 10 to 118 μm (B), and a polymerization initiator (C), the polymer powder contains a polymer powder having aspect ratio of 1.10 or more (B-x)； and a kit for repairing the hard tissue having a member in which each component of the monomer (A), the polymer powder (B) and the polymerization initiator (C) contained in the composition for repairing the hard tissue is divided in 3 or more with any combination and housed.SELECTED DRAWING: NoneCOPYRIGHT: (C)2019,JPO&INPIT【課題】組成物中の含水率の変化に因る硬化時間（セッティングタイム）の変動が低減された硬組織補修用組成物及び硬組織補修用キットを提供する。【解決手段】モノマー（Ａ）、体積平均粒径が１０～１１８μｍの重合体粉末（Ｂ）及び重合開始剤（Ｃ）を含む硬組織補修用組成物であって、重合体粉末（Ｂ）が、アスペクト比が１.１０以上の重合体粉末（Ｂ－ｘ）を含むことを特徴とする硬組織補修用組成物；並びに、この硬組織補修用組成物に含まれるモノマー（Ａ）、重合体粉末（Ｂ）及び重合開始剤（Ｃ）の各成分が、任意の組合せで３つ以上に分割されて収容された部材を有する硬組織補修用キット。【選択図】なし
