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

The method for producing the oxime from the ketone, the peroxide and the ammonia is characterized by reacting the peroxide with the ammonia in the presence of a catalyst on one side of a diaphragm and contacting the obtained reaction product with the ketone on the other side of the diaphragm. The catalyst is preferably supported on the surface of the diaphragm on one side of the diaphragm. The peroxide is preferably an organic peroxide.