Аннотация:The characterization of SS 433 as a massive, eclipsing binary system has been confirmed by the construction of continuous emission spectra of the 'normal' star and the accretion disk in the wavelength range of 3500 A to 2.2 microns. The investigation employed photometry of SS 433 at different phases of the orbital period as well as photometric data in the infrared range. The temperature of the normal star is about 20,000 K and its mass is greater than 10 solar masses. The optically thin accretion disk surrounds a relativistic object 'precessing' with a period of about 164 days. The spectrum of the projection of the disk can be described by a Planck function with temperature of 50,000 K or more. Its bolometric luminosity is 10 to the 40th ergs/s or more. The analogy between the processes taking place in the disk and those observed in galactic nuclei and quasars is pointed out.