To provide a paperboard feeding device which can be formed easily in a state to be provided sufficiently for paperboard of different width dimensions without requiring any setting operation at the time of start of feeding of the paperboard.

A device comprises a reversal lifter which sequentially takes out a number of paperboard X supported and taken in, in the state of being fallen down, reversibly about a reversal shaft relative to a machine frame 1, a delivery conveyor 40 which delivers the paperboard X taken out by the reversal lifter in the state of being fallen down one after another, and a transfer conveyor 60 which, after taking in the paperboard X from the delivery conveyor 40 and separating each piece of it, feeds the paperboard X again on a can manufacturing machine table Y. In this case, it further comprises stack detectors 93A to 93D which detect the level of the paperboard X stacked on the can manufacturing machine table Y and a feeding conveyor 60 of which base end part is supported liftably on the machine frame 1 by a support shaft 3. The feeding conveyor 60 is controlled liftably by those signals transmitted from stack detectors 93A to 93D so as to vary a paperboard X feed height according to the level of the paperboard X on the can manufacturing machine table Y.