PROBLEM TO BE SOLVED: To provide a stable oral dosage form comprising bendamustine, which can be easily administered to a patient and results in an improved bioavailability with less variability compared to known oral dosage forms.SOLUTION: There is provided a pharmaceutical composition in a solid dosage form suitable for oral administration, the composition comprising bendamustine or a pharmaceutically acceptable ester, salt or solvate thereof as an active ingredient, and at least one pharmaceutically acceptable excipient, which is a pharmaceutically acceptable saccharide selected from the group consisting of one or more of a monosaccharide, a disaccharide, an oligosaccharide, a cyclic oligosaccharide, a polysaccharide and a saccharide alcohol, wherein the ratio by weight of the active ingredient to the saccharide excipient(s) is in the range of 1 :1 to 10.SELECTED DRAWING: None【課題】患者に投与しやすく、かつ既知の経口剤形に比べて可変性が少ないバイオアベイラビリティーの向上をもたらす、ベンダムスチンを含む安定な経口剤形を提供する。【解決手段】経口投与に適した固体剤形の医薬組成物であって、活性成分としてのベンダムスチン又はその医薬的に許容できるエステル、塩若しくは溶媒和物と、1種以上の単糖、二糖、オリゴ糖、環状オリゴ糖、多糖及び糖アルコールから成る群より選択される医薬的に許容できる糖類である少なくとも1種の医薬的に許容できる賦形剤とを含み、活性成分と糖類賦形剤の質量比が1:1~10の範囲内である、医薬組成物。【選択図】なし