Abstract: This pharmaceutical composition contains a hydroxamic acid derivative, or a salt thereof, and a solubilizer, said hydroxamic acid derivative being selected from among (2S)-2-((4-((4-((1S)-1,2-dihydroxyethyl)phenyl)ethynyl)benzoyl)(methyl)amino)-N-hydroxy-N?,2-dimethylmalonamide, (2S)-2-((4-((4-((1R)-1,2-dihydroxyethyl)phenyl)ethynyl)benzoyl)(methyl)amino)-N-hydroxy-N?,2-dimethylmalonamide, and (2S)—N-hydroxy-2-((4-((4-((1S)-1-hydroxy-2-methoxyethyl)phenyl)ethynyl)benzoyl)(methyl)amino)-N?,2-dimethylmalonamide. The pharmaceutical composition demonstrates strong antibacterial activity, has excellent solubility in water, and is useful as a drug.