<;P>;PROBLEM TO BE SOLVED: To provide a mitochondrial fusion agent, etc., containing a new mitochondrial fusion peptide. <;P>;SOLUTION: The mitochondrial fusion agent, etc., contain a mitochondrial fusion peptide having an Asp-Pro structure and containing 2 to 3 amino acids as an active component. The peptide is preferably a dipeptide of Asp-Pro. <;P>;COPYRIGHT: (C)2011,JPO&INPIT