There are provided pharmaceutical formulations with improved oral absorptivity and injections that contain, as active ingredients, high concentrations of benzamide derivatives and their pharmaceutically acceptable salts, which are useful as histone deacetylase inhibitors. A pharmaceutical solution is prepared by dissolving a benzamide derivative or a pharmaceutically acceptable salt thereof in an organic solvent and/or acidic liquid, and a pharmaceutical formulation is prepared by adding a surfactant, an acidic substance and/or a polyethylene glycol. The present invention has enabled dissolution of benzamide derivatives or their pharmaceutically acceptable salts at high concentrations, to prepare practical injections and oral liquid formulations and improve absorptivity with oral administration.