A surgical fastener applying apparatus comprising a cartridge section (12) having a cartridge (16) containing a plurality of fasteners (130), an anvil section (14) having an anvil for receiving the fasteners when advanced from the cartridge, the cartridge and anvil sections clamping tissue therebetween. First and second cam members (110a,110b) are movable within the cartridge section to fire the fasteners. A cam member supporting member (150) fixed within the cartridge section has an upper surface on which the cam members are slidable. The upper surface of the cam member supporting member has a first upper surface portion (154) on a first plane and a second lower surface portion (152) in a different substantially parallel second plane such that the first and second cam members slide in offset planes on the upper surface to fire the fasteners.