The present invention relates to a process for producing an amide or lactam, particularly laurolactam, wherein catalytic amounts of an acidic chloride and a Lewis acid are used in Beckmann rearrangement of an oxime compound. In accordance with the process, side reactions during Beckmann rearrangement can be so controlled that selectivity can be improved and strong coloring in the reaction can be prevented, giving a high-quality amide or lactam.