Pressing an electronic device (2) to be tested to contact terminals (132a and 132b) while bringing a heater (112) having equal or close temperature change characteristics to those of the electronic device to be tested by a test pattern, transmitting a test pattern to the electronic device to be tested in this state, and controlling a power consumption of a heater so that total power of a power consumption of the electronic device to be tested by the test pattern and a power consumption of the heater becomes a constant value.