Disclosed is a method for efficiently producing an imidic acid salt represented by formula (I) with high selectivity, using a low-cost starting material. Specifically, an alkali metal fluoride, a sulfuryl halide or phosphoryl halide, and ammonia or an ammonium salt are reacted, when an imidic acid salt is produced. By this method, a desired imidic acid salt can be produced with high yield, while greatly suppressing the production of a byproduct. (In the formula, R represents a halosulfonyl group (-SO2X1 (wherein X1 represents a halogen (fluorine, chlorine, bromine or iodine))) or a dihalophosphoryl group (-POX2X3 (wherein X2 and X3 may be the same or different and each represents a halogen (fluorine, chlorine, bromine or iodine))); and M represents an alkali metal.)