PURPOSE: To control the received coal amount of a coal-charging hopper by automatically controlling the height position of a measure on the basis of the bulk density of charged coal.

CONSTITUTION: A measure 2 is disposed so as to be vertically moved with a cylinder 3 operated by control signals from a controller 5 and so that the height position of the measure 2 is detected with a sensor 4. The relation of the bulk density of charged coal with the height position of the measure and with the volume of the received coal is determined and preliminarily inputted into the controller. The inner volume of the target oven, the water content of the charged coal and the sizes of the coal pieces are inputted into the controller 5 to determine the bulk density, and the height position of the measure corresponding to the determined bulk density is compared with the height position-detected signal from the sensor to calculate the corrected value of the height position. The corrected value is outputted as a control signal into the electromagnetic switch valve 6 of the cylinder to control the height position of the measure. The charging amount of the charged coal charged into a carbonization chamber can be suitable secured.