A thermal oil furnace directly inserts an electric heater into an organic carrier (thermal oil) for direct heating, and then circulates the heated thermal oil through a high-temperature oil pump to deliver it to the heat-using equipment. The oil is returned to the electric thermal oil furnace from the outlet of the heat-using equipment, completing a full cycle heating system. The electric thermal oil furnace features a digital temperature controller for precise temperature control, with functions for over-temperature, low oil level, and over-pressure alarms.