Abstract: To provide a process of hydrocracking heavy oil capable of obtaining cracked light oil with higher yields and/or milder reaction conditions than the conventionally proposed hydrocracking process in a suspended bed method using an iron-based catalyst when hydrocracking heavy oil containing heavy metal components produced in a refining process of crude oil into lighter oil. There are provided (1) a process of hydrocracking heavy oil containing heavy metal components produced in a refining process of crude oil, comprising a vacuum distillation step to obtain the heavy oil as distillation residue by vacuum distillation; and a reaction step to hydrocrack the heavy oil in the presence of an iron-based catalyst in a suspended bed reactor, wherein the distillation is conducted at 350° C. or less in the vacuum distillation step, (2) in the preceding process, reaction conditions in the reaction step are a reaction pressure of 60-160 kg/cm2; a reaction temperature of 430-455° C.; and a reaction time of 30-180 minutes.