PURPOSE: To remove the influence of the weight of material to be heated with simple and sure operations by a constitution wherein a weight sensor is provided within a compartment and the shielding wire of the sensor is connected through a terminal arranged onto the wall of the compartment to a control circuit in the high frequency heating device of foodstuff or the like.

CONSTITUTION: The weight sensor 9 is placed on a top board 8 and the plug 11 of the shielding wire 10 is inserted in the terminal 12. Material to be heated 2 is placed on the weight sensor 9 and the kind of the material to be heated is set by the selector key on the operating panel (not shown) before cooking is started. Consequently, the heating time is determined based upon the weight detection signal of the weight sensor 9 and a high frequency oscillator 4 is controlled by the control circuit 3. Due to the constitution as mentioned above, the operation becomes simple and sure and yet the influence of the weight can be eliminated.