A pharmaceutical composition containing the substance according to any one of the following (a) to (c), an organic acid, a metal salt of an organic acid, and a sugar and/or a sugar alcohol, wherein when the pharmaceutical composition is dissolved in distilled water for injection, a pH of the pharmaceutical composition is 3.0 to 4.5, the substance according to any one of the following (a) to (c) can be stabilized;



(a) an HMGB1 fragment peptide comprising the amino acid sequence set forth in SEQ ID NO: 1 or an acid addition salt thereof;
(b) a peptide comprising an amino acid sequence having substitution, deletion, insertion or addition of one or more amino acids in the amino acid sequence set forth in SEQ ID NO: 1, and having an activity of stimulating migration of a cell, or an acid addition salt thereof; and
(c) a peptide comprising an amino acid sequence having about 80% or more of sequence identity to the amino acid sequence set forth in SEQ ID NO: 1, and having an activity of stimulating migration of a cell, or an acid addition salt thereof.