The present invention relates to a therapeutic tool for vascular diseases, which is coated with a dye-containing resin that comprises one or more biocompatible dyes selected from the group consisting of sulfonic acid azo dye, phthalein dye, triphenylmethane dye, phenantridium dye, acrydine dye, xanthene dye, phenothiazine dye and cyanine dye; a medical treatment by the use of the therapeutic tool for vascular diseases; and a method of preventing vascular restenosis caused mainly through inhibition of migration of vascular progenitor cells by administering the medical treatment to a subject. Since the present therapeutic tool for vascular diseases is capable of staying in vivo for a long term, a medical treatment such as angioplasty (coronary angioplasty, peripheral angioplasty, cerebral angioplasty, etc.) and blood vessel bypass (coronary bypass, peripheral bypass) by the use of the present tool can effectively inhibit the generation of blood vessel restenosis by inhibiting migration of vascular progenitor cells. Thus, the present tool is extremely useful in clinical situations.