A kind of dwell time of the system of the present invention the time required to can shorten until it can carry out good processing job state to be provided, as a result, become the short time by the time needed for making until starting to process operation, the bone cement constituent of high operating efficiency can be made, and to be made for the purpose of the manufacturing method of bone cement constituent set group when bone cement constituent and bone cement hardenite.The bone cement constituent of the present invention, it is 10~60 μm of its big particles of (methyl) acrylic ester polymer that its characteristic, which is containing average grain diameter, average grain diameter is 0.1~2.0 μm of its (methyl) acrylic ester polymer small particle particle, (methyl) acrylate monomer and polymerization initiator, and the content ratio of aforementioned (methyl) acrylic ester polymer small particle particle, opposite what is 5~30 mass % for being somebody's turn to do the total amount of (methyl) acrylic ester polymer small particle particle and the big particle of (methyl) acrylic ester polymer.本發明係以提供一種可縮短直至可進行良好的處理作業狀態為止所需時間的停止時間，結果，藉由使直至開始處理作業為止所需的時間變為短時間，可製得高作業效率之骨水泥組成物，及為製得骨水泥組成物時之骨水泥組成物套組，以及骨水泥硬化體之製造方法為目的。本發明之骨水泥組成物，其特徵為含有平均粒徑為10～60μm之(甲基)丙烯酸酯系聚合物大粒徑粒子、平均粒徑為0.1～2.0μm之(甲基)丙烯酸酯系聚合物小粒徑粒子、(甲基)丙烯酸酯系單體與聚合引發劑，且前述(甲基)丙烯酸酯系聚合物小粒徑粒子之含有比例，相對於該(甲基)丙烯酸酯系聚合物小粒徑粒子與(甲基)丙烯酸酯系聚合物大粒徑粒子之合計量而言為5～30質量%。
