A structure for assembling a vehicle interior lighting, comprises a lens, a socket, a cover fitted to the socket, a first regulation portion configured by one side of the fitted cover or the fitted socket that is located on a front side in the insertion direction and a part of the lens, the first regulation portion regulating forward movement of the cover or the socket in the insertion direction; and a second regulation portion configured by another side of the fitted cover or the fitted socket that is located on a rear side in the insertion direction and a part of the lens, the second regulation portion regulating backward movement of the cover or the socket in the insertion direction.