A cyclododecanone compound is continuously produced by feeding a liquid feed containing a corresponding epoxycyclododecane compound and LiBr and/or LiI into a frontmost reaction region of a plurality of reaction regions connected to each other in series; successively passing the liquid feed through the series of reaction regions to catalytically isomerize the epoxycyclododecane compound into a corresponding cyclododecanone compound; and collecting the resultant reaction mixture containing the target cyclododecanone compound from a rearmost reaction region of the series of reaction regions.