Abstract: A powder feeding device comprising a metering hopper for metering a powdery material supplied from a holding hopper, a weight measuring device for measuring the weight of the powdery material in the metering hopper, a device for opening and closing a discharge opening formed in the metering hopper and a control device for controlling the action of the opening and closing device. The control device has a timer, a device for setting a discharge interval, and a device for correcting the standard discharge interval set by the discharge interval setting device. The discharge interval correcting device corrects the standard discharge interval on the basis of a measured signal from the weight measuring device.