To provide a temperature adjusting plate, for keeping a semiconductor wafer accurately at a constant temperature during a burn-in test.

A wafer 50 is held constant at a given temperature by a temperature adjusting plate 1 through electrical continuity. The temperature adjusting plate 1 includes a cooling liquid path 6 which becomes larger from the center to the circumferential part thereof in a good thermal conductive disk plate 2, an electrical heater 7 with heating wires put more densely from the center to the circumferential part, temperature sensors 5a to 5c, and a temperature controller (C). Then, according to the difference in the temperatures of the wafer, the temperature of the central part is made lower than that of circumferential part of the wafer.