Using Neutron Radiography (NR), the transfer of lithium ions has been investigated in the high temperature-type lithium ion conductor, Li1.33Ti1.67O4. After supplying direct current to the oxides with different isotope ratios (Li-6/Li-7), NR Images were obtained, which confirmed lithium ion movement in the oxides as changes of bright parts on negative films. Analysis of the NR images clarified that lithium ions in the spinel-type Li1.33Ti1.67O4 were transported almost reversibly according to the polarity of electric field applied. The relations between the lithium contents in the samples and the film gray level showed that the cathode region in the charged sample contains about twice more lithium than in the original sample. Furthermore, NR method was applied to check lithium ion insertion into the TiO2 (rutile) sample. As a result, an informative Neutron Radiogram showing the lithium ion insertion was obtained.