Hydrocracking process, and a method for manufacturing a hydrocarbon oil

The hydrocracking method of wax fraction included in the Fischer-Tropsch synthetic oil hydrocracking, a wax fraction hydrocracking step to obtain a hydrocracked product, the multi-stage gas-liquid separator, the hydrogen a gas-liquid separation step of separating the reduction decomposition products into a gas component and heavy oil component and the light oil component, wherein the determined flow rate ratio of the heavy oil component and the light oil component, from the flow rate ratio, the hydrogen contained in the reduction decomposition product, and the particular component amount estimating step for obtaining the estimated value of the content of the specific hydrocarbon component, based on the estimated value, the content of the specific hydrocarbon component a predetermined range as such, a control step of controlling the operation of the wax fraction hydrocracking process.