(Objective) An objective of the present invention is to provide therapeutic agents that, in association with stimulation of PDGFRα-positive cells such as bone marrow mesenchymal stem cells, promote their mobilization into blood and accumulation in a damaged tissue, and induce tissue regeneration in a living body.(Means for solution) Multiple peptides were synthesized, and the migration-promoting activity of each peptide was evaluated. As a result, the present inventors successfully identified multiple peptides that have migration-promoting activity on a PDGFRα-positive bone marrow mesenchymal stem cell line (MSC-1). Further, the present inventors confirmed that the identified peptides also have migration-promoting activity on skin fibroblasts, which are PDGFRα-positive cells.