Neutron Rietveld refinement has been performed to elucidate structural changes due to Na+/Li+ exchange in one-dimensional tunnel-like cavities of sodium titanogallate NaxTi2-xGa4+xO10(x approximate to 0.85). Cell parameters were anisotropically changed by ion-exchange; a, b and c have changed by - 0.232, + 0.014 and - 0.039 Angstrom on substitution of Li+ for Na+ respectively. Three L+ sites have been found in the Li-derivative; two of them are a little displaced from the two-fold rotation axis through the tunnel center, while the other is the deformed tetrahedral site fairly apart from the tunnel center. These results are basically different from those for Na+ ions in the parent compound.