We have performed 106 subclavian vein punctures under the ultrasonic guidance. The linear array, electronic real-time scanner has made it possible to visualize not only the subclavian vein, the subclavian artery, the rib and the lung but also the needle and the catheter. In all cases, the subclavian veins were detected and the mean diameter of them was 10.5±2.2 mm. Success rate of cannulation was 102/106 (96.2%) and complication was only one hematoma (0.9%). Pneumothorax was not observed. It was concluded that the use of this method could increase the success rate of cannulation and prevent the complications. For the visualization of the subcutaneous layer and the wall of vessels, 7.5 MHz probe was suitable for more precise monitering of them. For the close contact and the easy handling at the narrow space of infraclavicular region, small size probe was useful. From now, development of the ideal adaptor for the small size probe that allows free selection of angle is required.