There will be provided a punching unit capable of reliably drawing a punch out of the workpiece, improving the productivity and without deteriorating the boring precision even for a workpiece which easily spreads, and preventing leavings rising. A stripper plates which has been positioned close to the workpiece in accordance with the thickness thereof does not press the workpiece, but draws the punch during rising out of the workpiece to transmit the striking driving force of the electric motor to the movable die holding the punch. In an air path portion arranged within the machine frame, there is provided means for opening or closing through an electric signal and the air path between the air ejecting unit and the means is made shorter, whereby the response to air ejection is improved, the pressure loss during air flow is reduced to a minimum, and jet air is accurately applied to punching chips (leavings) which adhere to the punch at the bottom dead center for peeling off the punch.