PROBLEM TO BE SOLVED: To provide a method of producing a lithium carbonate capable of producing a lithium carbonate from salt water resources including a large amount of interference components such as magnesium and sulfate ions and operable in highlands and inlands where inexpensive sodium carbonates such as natural soda ashes are hardly available.SOLUTION: In a method of producing a lithium carbonate, a crystal of a lithium carbonate is precipitated in a carbonization process of introducing a carbon dioxide gas, which is obtained by burning limestone in the coexistence of ammonia, to concentrated salt water prepared from a lithium-containing salt water via a desulfurization process, an evaporative concentration process and an electrodialysis process; and the precipitated crystal is collected by solid-liquid separation.