PROBLEM TO BE SOLVED: To provide a stable solid medical preparation containing as an antiulcer drug a compound useful as a proton pump inhibitor (PPI) unstable in not only acid but in water and the like.SOLUTION: A solid preparation contains a non-toxic base and a benzimidazole compound represented by formula (I) of an amorphous form with PPI action. (ring A is a substituted/unsubstituted benzene ring； Ris H, a substituted/unsubstituted aralkyl group, an acyl group, or an acyloxy group； Rto Rare H, a substituted/unsubstituted alkyl group, a substituted/unsubstituted alkoxy group, or a substituted/unsubstituted amino group each independently； Y is N or CH； and * is an asymmetric center)【課題】消化性潰瘍治療剤として酸だけでなく、水等にも不安定なプロトンポンプインヒビター（ＰＰＩ）として有用な化合物を含有する、安定な医薬用固形製剤の提供。【解決手段】無毒性塩基とＰＰＩ作用をもつ非晶形の式（Ｉ）で表されるベンズイミダゾール系化合物とを含有する固形製剤。（環Ａは置換／非置換のベンゼン環；Ｒ１はＨ、置換／非置換のアラルキル基、アシル基又はアシルオキシ基；Ｒ２～Ｒ４は各々独立にＨ、置換／非置換のアルキル基、置換／非置換のアルコキシ基又は置換／非置換のアミノ基；ＹはＮ又はＣＨ；＊は不斉中心）【選択図】なし
