A method of detecting an abnormality in a burn-in apparatus, which brings a heater and a temperature sensor into contact with various devices under test during a burn-in test and controls power consumption of the heater to adjust levels of temperature of the devices under test, wherein the temperature sensor detects temperature of a temperature control block in which the heater and the temperature sensor are arranged and with which a cooling liquid is in contact while the devices under test are not in contact with the heater and the temperature sensor, and the temperature sensor is diagnosed to be normal or not based on a result of detection.