Disclosed is a vehicle interior illumination structure comprising, in combination, an instrument panel 10 installed in a front interior area of a vehicle, and a light-guiding illumination member 2 disposed in the instrument panel. The instrument panel 10 is formed with a step portion S laterally extending at a height approximately equal to or above that of a mounting portion of a shaft of a steering wheel 35 to the instrument panel. The step portion S is defined in such a manner that a step upper surface 11f located on the upper side of the step portion and a step lower surface 12f located on the lower side of the step portion are formed in the instrument panel 10, and the step upper surface 11f has a rear edge 11p protruding in the rearward direction of the vehicle relative to a front edge 12p of the step lower surface 12f. The illumination member 2 is arranged to extend laterally at a position which is adjacent to the front edge 12p of the step lower surface 12f and capable of preventing illumination light of the illumination member 2 from directly coming within the field of view of a driver sitting in a front seat in the vehicle interior. The vehicle interior illumination structure of the present invention can prevent illumination light of the illumination member from obstructing the driver's view.