Lithium ion diffusion processes in pulsed laser-deposited TiO2 film electrodes are investigated by electrochemical and isothermal transient ionic current (ITIC) methods. Cyclic voltammogram and potential step measurements are used to examine the processes of insertion of Li ions into the TiO2 electrode. Two diffusion processes of Li ion, driven by the concentration gradient and by an applied field, are demonstrated by ITIC analysis. The diffusion constants are dependent on the measuring method and the diffusion mechanism. These results clarify the diffusion behavior of Li ion in anatase Ti02 film and prove that pulsed laser deposition is a promising method for producing TiO2 film electrodes.