A cyclododecanone compound is continuously produced by an isomerization reaction of a corresponding epoxycyclododecane compound in the presence of a catalyst including lithium bromide and/or lithium iodide, the isomerization reaction being carried out by passing a reaction mixture containing the epoxycyclododecane compound and the catalyst through a continuous reaction apparatus including at least one tubular reactor preferably at a temperature of 100 to 350° C.