Provided is a molten salt battery which comprises: a positive electrode that contains a positive electrode active material represented by general formula An(1-x)M1 nxFe1-yM2 yP2O7 (wherein n is 1 or 2, 0 <=x<=0.5, 0<=y <=0.5, A represents an alkali metal element, M1 represents an element other than an alkali metal, and M2 represents an element other than Fe); a negative electrode that contains a negative electrode active material; a separator that is interposed between the positive electrode and the negative electrode; and a molten salt electrolyte. The molten salt electrolyte contains 90% by mass or more of an ionic liquid that contains a salt of the element A.