Recently, surface plasmon resonance (SPR) and enzyme-linked immunosorbent assays (ELISA) have emerged as prevalent methods in cancer diagnostics. However, these techniques often struggle with the detection of minimal quantities of reagents and molecules. To address these limitations, our research group has pioneered the development of terahertz chemical microscopy (TCM).In this study, the antigen-antibody response was measured using anti-CD63 as the antibody and exosomes derived from H1299 lung cancer cell lines (H1299 EV) as the antigen. When exosomes are immobilized on the terahertz chemical microscopy's sensor surface, the electron distribution in the molecule changes, and the surface potential of the silicon oxide film changes. The emitted terahertz wave intensity depends on the change in the depletion layer electric field. By comparing terahertz wave intensity measurements before and after the reaction, the exosome antigen-antibody reaction was successfully detected.