To provide a method of efficiently producing a cycloalkanone oxime in high yield.

A cycloalkanone oxime is efficiently produced through the following steps: The step (A) where a cycloalkane is reacted with nitrogen oxides in the presence of a specific imide (the reactor 1), the step (B) where the non-crystallized component including nitrocycloalkane and the crystallized component including the catalyst and the cychloalkanone oxime are separated from the reaction mixture (the crystallization tank 3 and the filter 4), and then the catalyst is separated from the crystallization component (the repulping tank 5 and the filter 6) while the cycloalkanone oxime is separated from the filtrate (distillation columns 7, 8). The cycloalkanone oxime is produced with high efficiency by those steps. In another embodiment, the reaction mixture from the reactor 1 may be concentrated in the concentration step (C) (the concentrator 2).