This paper describes a new sensor system for effective evaluation of surgical skill. This system used photo interrupter in order to detect the movement of skin dummy during suture placement. Experimental results show that the data obtained from this sensor are significantly different among surgeons and non-medical volunteers from a few aspects. We proposed the differences as evaluation parameters to evaluate suture skill using this system. The effectiveness of this evaluation parameters was confirmed when surgeons' data and non-medical volunteers' data are divided effectively using Discriminant Function Analysis. One of the advantages of this system is it can be develop at low cost. In future, this sensor system will be embedded in patient robot application