Disclosed is a corrugated paperboard box making machine 1 in which a slotter device 6 comprises: a first slotter unit 61 comprising a first slotter 610, a first stationary blade 612 and a first displaceable blade 613; and a second slotter unit 62 comprising a second slotter 620, a second stationary blade 622 and a second displaceable blade 623. A control device 100 is operable to switch the slotter device 6 between a first production mode and a second production mode. Specifically, the control device 100 is operable, when implementing the second production mode, to acquire and store a total blade length of the first stationary blade 612 and the first displaceable blade 613 and a total blade length of the second stationary blade 622 and the second displaceable blade 623, and perform positioning control for the slotter blades, based on the stored total blade lengths.