In the actual Endoscopic Submucosal Dissection (ESD) procedures, lesion marking is performed to clarify shapes and boundaries using Indigo carmine for tumors prior to resection. Accurate marking at a certain distance around the tumor is important for complete resection of the tumor as well as shortening of the procedure time. However, it is not easy to mark the precise location around the tumor especially in novices physicians. Visual guidance for proper marking location would be helpful to improve the task performance. however, there was no attempts to provide a guidance in ESD task as far as the authors know. Therefore, in this study, an automatic guidance for lesion marking is proposed endoscopic robot system. Its effectiveness in marking task performance is evaluated as well.