A TiO2 film was fabricated by a simple electrochemical method using a sacrificial titanium anode as a cationic source in an I-2-dissolved acetone bath, where the solvent contains iodide ions as a supporting electrolyte but no Ti salt as an electrolyte. At the initial stage of electrolysis, anodic oxidation of Ti anode occurred under the presence of water as an impurity to acetone. Subsequently, TiO2+ was produced as a result of the dissolution of oxide films under the influence of iodide ions, and was then electrodeposited on the cathode surface. The morphologies of as-deposited films were found to be dependent on the film thickness, which in turn is determined by the voltage applied during the electrolysis. Moreover, the obtained films show photocatalytic activity for decomposition of gaseous acetaldehyde without annealing. In this paper, the electrodeposition mechanism is discussed in detail.