The solubility of LaCl3 in acidic AlCl3–1-ethyl-3-methylimidazolium chloride (AlCl3–EMICl) ambient temperature melts at 298 K increases as the acidity of the melts increases. When LaCl3 was dissolved in the melt (molar fraction of AlCl3, N=0.667), Raman spectra of AlCl4 − and Al2Cl7 − anion were observed. From these results, the dissolution reaction in the acidic melts is thought to be: 3Al2Cl7 −+LaCl3⇄La(III)+6AlCl4 −. Electrochemical measurements and potentiostatic electrolysis were performed in various LaCl3 saturated AlCl3–EMICl melts. The electrodeposits obtained at more negative potential than −0.18 V versus Al(III)/Al in a LaCl3 saturated acidic melt (N=0.667) were pure aluminum metal. It was suggested that lanthanum metal electrodeposits at around −1.95 V in the LaCl3 saturated melt (N=0.667) after addition of excessive LiCl and 50 mmol kg−1 of SOCl2.