To provide a method for producing an oxime from a ketone, an organic peroxide and ammonia in a good yield, while reducing the production of by-products obtained by the reaction of the ketone with ammonia.

The method for producing the oxime from the ketone, the organic peroxide and ammonia is characterized by placing the ammonia on one side of the diaphragm and reacting the ammonia penetrated the diaphragm, the organic peroxide and the ketone in the presence of a catalyst on the other side of the diaphragm. The catalyst is preferably supported on the surface of the diaphragm on the other side of the diaphragm.