Enamel demineralization often occurs in the early stage of dental caries. Studying the microscopic mechanism of enamel demineralization is essential to prevent and treat dental caries. Terahertz (THz) technology, especially continuous wave (CW) THz near-field scanning microscopy (THz-SNOM) with its nanoscale resolution, can be promising in biomedical imaging. In addition, compared with traditional THz time-domain spectroscopy (TDS), portable solid-state source as the emission has higher power and SNR, lower cost, and can obtain more precise imaging. In this study, we employ CW THz-SNOM to further break the resolution limitations of conventional THz imaging techniques and successfully achieve the near-field imaging of demineralized enamel at the nanoscale. We keenly observe that the near-field signal of the enamel significantly lowers as demineralization deepens, mainly due to the decrease in permittivity. This new approach offers valuable insights into the microscopic processes of enamel demineralization, laying the foundation for further research and treatment.