Fundamental experiments are conducted to confirm the calcium reactivity with titanium oxide in the molten calcium chloride. The TiO2 samples placed in the molten salt could be reduced without any electron supply to TiO2. In the close vicinity of cathode, TiO2 could be successfully reduced to alfa-Ti with 1600 mass ppm oxygen. However, the strong stirring of the melt disturbed the calcium distribution near the cathode and the reduction was incomplete. These findings supported the proposed mechanism that Ca deposited on the cathode and it dissolved immediately into the molten salt. The parasite reactions consumed the dissolved Ca quickly, and they suppressed the effective reduction and subsequent deoxidation.