A
surgical stapling instrument including a selectively actuatable
cutting member. The stapling instrument may be used as a surgical stapler without
cutting tissue or, if desired, the surgeon may selectively actuate the
cutting member to
cut tissue as the staples are being deployed and formed. A stapling instrument can include an
actuator knob that has at least one pusher bar attached thereto. Advancement of the
actuator knob in a distal direction causes the pusher bars to apply a firing motion to the staples contained within a staple
cartridge supported within the stapling instrument. A knife bar may be selectively coupleable to the
actuator knob by a selector switch that is movable from an actuated position wherein movement of the actuator knob in the distal direction advances the knife bar which has a cutting blade portion to advance between rows of staples in the staple
cartridge to an unactuated position wherein movement of the actuator knob advances the pusher bars without advancing the knife bar.