An electrolyte for iron-air batteries, which is able to increase the discharge capacity of iron-air batteries without concentration control, and an iron-air battery using the electrolyte. The electrolyte for iron-air batteries having an anode containing an iron element may comprise an aqueous solution comprising a discharge reaction promoter containing at least one kind of anion selected from the group consisting of SCN− anions, S2O32− anions and (CH3)2NCSS− anions.