PURPOSE: To prevent congestion of coal inside a coal throwing-in tank when operation of a belt conveyor, which has stopped, is started.

CONSTITUTION: In a coal feeder provided with a coal throwing-in tank 1, to which coal is supplied from the outside, and a belt conveyor 5, which is arranged below the coal throwing-in tank 1 and conveys the coal dropped from the coal throwing-in tank 1 to a coal feeding port, 6, a level switch 14 detecting the thickness of a coal layer inside the coal throwing-in tank 1 is installed in the lower part, of the coal throwing-in tank 1, and operation of the belt conveyor 5 is continued if the coal layer thickness detected by the level switch 14 is the predetermined value or more when the belt conveyor 5 is stopped. When the coal layer thickness detected by the level switch 14 becomes the predetermined value or less, operation of the belt conveyor can be stopped.