Abstract: [Problems] An injection preparation containing a depsipeptide having a disulfide bond in its molecule, which can be easily prepared, and which is stable, is provided. [Means for Solution] An injection preparation having a long-term stability can be provided by compounding a substance such as ferric chloride, making the solution to have a pH which is not higher than 7.0 and which is not lower than 1.0, and carrying out nitrogen replacement. [Advantages of the Invention] The injection solution of the present invention is expected to provide an injection preparation in which formation of aggregate and cluster of a depsipeptide having a double bond in its molecule is avoided and which is excellent in a storage ability.