Many dermatological studies have had limited success in revealing skin functions as conventional dermatological methods are known to affect the components in the skin. Recent progress in non-invasive optical imaging has enabled us to visualize the structure of each skin layer non-invasively. However, it is still difficult to identify individual skin components. On the other hand, we can obtain the molecular vibrational signature using spontaneous Raman scattering spectroscopy. However, this technique requires long acquisition times and is rarely applied to skin imaging. Therefore, we have also applied non-linear spectroscopy, coherent anti-Stokes Raman scattering (CARS), and stimulated Raman scattering (SRS) to acquire more rapid molecular imaging of the skin. In this paper, the applications of spontaneous Raman spectroscopy to human skin evaluation in vivo and the latest results of 3D intracellular morphologies in the epidermis in humans during differentiation using coherent Raman scattering microscopy are introduced.