The purpose of this study is development of a Blood Collection Assistance System (BCAS) for accident prevention. Previous studies have developed assistance units for vein detection and vein puncture, which are difficult operations. However, the large size (400×330×440mm) of the units tend to place a psychological burden on users and errors occurring in each unit are large. This study aimed to achieve downsizing the equipment, improvement of the needle control accuracy and integration of the control system. The puncture unit was downsized (195×170×210mm) with redesign. The error in vein detection was 2.6mm (max) which was larger than the target accuracy of 0.1 mm for safety puncture, depending on the position of near infrared illumination. The maximum errors of needle positioning, directing and puncturing were 0.09mm, 0.59° and 0.21 mm, respectively. As the standard deviation was small, it seems that optimization of the control system could reduce the error.