We have developed 'Cavitas sensors' into human cavitas sites of oral cavity for non-invasive monitoring of saliva glucose. A salivary biosensor based on the integration of working electrode with an enzyme membrane on a mouthguard was fabricated and demonstrated. This mouthguard biosensor was integrated with a glucose sensor and wireless measurement system. In the investigation of in-vitro characterization, the biosensor showed excellent relationship between the output current and the glucose concentration. In artificial saliva consisting of salts and proteins, the glucose sensor exhibits highsensitive detection in a range of 5-1000 μmol/L. We demonstrated the capability of the sensor and wireless communication module to characterize an inclusion in oral phantom that imitative structure of human oral cavity. The mouthguard biosensor would be useful for real-time and non-invasive method as a novel health care management.