The present invention relates to a blood vessel inner wall analyzing apparatus provided with a structure for more accurately analyzing components of substances adhered to the inner walls of blood vessels. A blood vessel inner wall analyzing apparatus (1) is provided with illuminating means, detecting means and analyzing means. The illuminating means illuminates a light component in a measurement wavelength range of 1957 nm to 2713 nm onto a measured position from an end surface (30b) of a light illuminating fiber (30) inserted into a carotid artery (C). The detecting means receives a light component from a measured position through an end surface (40a) of a light receiving fiber (40) within the carotid artery (C). The light component to be detected is a light component in a detection wavelength range which extends 15 nm on both short and long sides of the selected center wavelength, with each one or more center wavelengths being selected from a wavelength group comprised of specific wavelengths respectively in the measurement wavelength range. The analyzing means analyzes for the presence or absence of substances differing from blood by using intensity information on the detected light component.
