A cooking apparatus comprising a rotary table disposed inside a heating chamber so as to mount food to be heated, and a motor which rotates the rotary table. The rotary table and the motor are integrally supported in a floating state by a resilient member, thereby allowing the food and the rotary table to vibrate or move vertically. This vertical vibration or movement is measured by employing a detector, and the weight of the food is measured from the output of the detector. The rotary table is provided with a biasing means interlocked with a door for regulating the height of the rotary table or stabilizing the same when the door is opened. In the case where the vibration of the rotary table is particularly detected, the rotary table is forced to vibrate by the action of the biasing means thereby allowing highly accurate measurement of the weight of the food. The output of the heating source, the heating mode and the heating time are controlled in correspondence with the measured weight of the food, and it is therefore possible to improve the cooking apparatus such that it is conveniently used and to realize a finely controlled heating operation.