Abstract: The present invention relates to a pharmaceutical composition comprising a microRNA (miRNA) inhibitor as an active ingredient for the prevention or treatment of a vascular smooth muscle cell proliferative disease; a kit comprising a miRNA-detectable agent for the diagnosis of a vascular smooth muscle cell proliferative disease; a method for providing information for the diagnosis of the diseases; and a therapeutic method. Discovered in the present invention were the miRNA subsets miR-132-3p, miR-370-3p, miR-130b-5p, and miR-410-3p that are involved in proliferative diseases of smooth muscle cells. It was found that these miRNAs significantly increased their expression 5-fold or more in damaged arteries, compared to the control, and in particular, miR-370-3p was highly expressed in coronary tissues of atherosclerosis patients. Thus, the miRNAs can be advantageously used for diagnosing diseases related thereto and further can find applications in treating vascular smooth muscle cell proliferative diseases.