© 2020 IEEE. Flexible endoscopic surgery has been developed as a minimally invasive surgery. The surgeon has been facing problems with insufficient information on grab state of forceps and organs hardness during the surgery. This paper reports a unique tactile sensor based on structural color changes to solve the problem. It can detect three-axis forces with very simple structure to provide structural color information. Since the force detection principle uses only the existing endoscope's camera to get hue (structural color) change on the device surface, additional signal transmission elements such as electrical wires, optical fibers, and battery are not required for the tactile sensor drive. The fabricated devices demonstrated wireless three-axis force sensing and hardness discrimination for the first time, and it makes it possible to apply tactile sensing to flexible endoscopic surgery.