Recently, endovascular interventions such as balloon angioplasty, atherectomy and the stenting method, except for conventional surgery have been clinically employed for the patients with atheromatous plaques of the peripheral and the coronary arteries, because the number of patients with arteriosclerosis is now increasing in the worldwide. Among these procedures, restenoses after endovascular interventions have been remarkably disclosed in 20-40% of the patients who underwent percutaneous coronary interventions. Thus, there are still some problems in keeping long-term patency by means of endovascular techniques such as balloon angioplasty and atherectomy. For reduction of these problems, laser angioplasty using Argon laser was applied experimentally and clinically. Based on excellent experimental studies, laser was employed for 115 patients with stenotic, or obstructive lesions occluding more thasn 75% of the peripheral and the coronary arteries angiographycally.