Early detection of dental caries is critical for avoiding more invasive and advanced treatment at a later stage. However, currently available techniques are unsatisfactory for early detection. Raman spectroscopy is known to have both high sensitivity and specificity in the analysis of mineral content in a tooth; but translating Raman spectroscopy to clinical caries detection remains a challenge. In this study, we report a full-scale Raman imaging system that can provide fast full-scale (~7 mm in diameter) tooth mineral analysis which could be feasible for clinical application. The results show that the Raman imaging system could not only confirm carious lesions that are obvious to the naked eye but also identify those which are not conclusive to traditional visual examination and probing.