To sterilize bacteria adhering to or existing on Wakkanai diatomaceous shale itself and simultaneously disinfect or sterilize bacteria existing externally. An environment improving material containing Wakkanai diatomaceous shale granules and/or powder having a disinfection, sterilization or inactivation function by a sterilization process and configured so as to disinfect, sterilize or inactivate microorganisms.本發明提供一種環境改良材料及其製造方法。本發明的課題是在將附著、存在於稚內矽藻頁岩自身的細菌進行滅菌,並且對存在於外部的細菌也進行殺菌或滅菌。解決方案是前述環境改良材料含有經滅菌處理而具有殺菌或滅菌或者去活化功能的顆粒體及/或粉末體的稚內矽藻頁岩,將微生物進行殺菌或滅菌或者去活化。
