Using multi spectral imaging technology, which enable us to simultaneously obtain spatial and wavelength information, we have newly developed blood vessel viewer. Our device is composed of the light source, the lens or the endoscope, the optical device, CCD camera, and PC. As an evaluation of our device, we measured the skin diffuse reflectance spectrum of the human hand. The blood vessel observed by our device was corresponding to an anatomy finding. However, even if Principal Component Analysis was used, the reflection of horny was not able to be removed completely.