The cavity dispersion nonaxiality (CDN) in a self mode locked solid state laser is calculated. It is shown that the transverse effect of CDN is not less than that of self focusing in most of the stability regions and seriously affects the generation and the compression of the self mode locking pulse. The experimental results prove that the self mode locked regime of a Ti: sapphire laser without hard apertures is in the vicinity of the point where the cavity axes are coaxial in the gain medium.