This pharmaceutical composition for oral administration contains, as an active component, a 4-((1-methylpyrrole-2-yl)-carbonyl)-N-(4-(4-morpholine-1-yl-carbonyl piperidine-1-yl)-phenyl)-1-piperazinecarboxamide or a salt or solvate thereof, and contains, as an acidic additive, adipic acid, succinic acid, fumaric acid, L-aspartic acid, L-glutamic acid, or any combination of these.