Disclosed are: a powder which exhibits good adhesion to the skin and has excellent dispersibility in an oil component or water and a long-lasting cosmetic preparation which glides excellently smoothly during application and forms an excellently uniform cosmetic film. Specifically disclosed are: a flat cellulose powder processed with an amphiphilic substance, which is obtained by mechanically pulverizing a cellulose-based substance and one or more amphiphilic substances that are selected from the group consisting of phospholipids, ceramides, cholesterol and derivatives thereof, and phytosterols and derivative thereof and a cosmetic preparation which contains the powder.本發明之目的在於提供一種對皮膚之附著性佳、對油性成分或水之分散性優異,以及一種塗佈時之滑潤感及化妝膜之均勻性優異的粉體、化妝持久性佳之化妝料。該化妝料,係將纖維素系物質、與選自磷脂質、腦醯胺、膽固醇或其之衍生物、植物固醇或其之衍生物所構成群中之兩親媒性物質之1種或2種以上,經機械性之粉碎處理所得之兩親媒性物質處理的扁平纖維素粉體及含有該粉體之化妝料。
