A method for producing -caprolactam and a method for reactivating a zeolite catalyst for the production are provided. In the reactivation step, a zeolite catalyst is allowed to contact a gas containing a carboxylic acid, water and a compound selected from ammonia and amines. In accordance with the present invention, the catalytic activities of a zeolite catalyst used for the Beckmann rearrangement reaction of cyclohexanone oxime can be effectively restored. Consequently, -caprolactam may be produced with a high production yield for a long period of time by reusing the catalyst by the method described above.