Provided is a method for producing a lubricant base oil whereby a lubricant base oil having a high viscosity index can be produced at high yield. One embodiment of the method for producing a lubricant base oil according to the present invention comprises: hydrogenating a petroleum-origin hydrocarbon oil in an atmosphere with a hydrogen partial pressure of 11-20 MPa at a reaction temperature of 250-420oC to prepare an oil to be treated that has an aromatic hydrocarbon content of 10-25 mass%; and a step for subjecting the oil to be treated to hydroisomerization.