A surgical fastener applying apparatus comprising a cartridge section having a cartridge containing a plurality of fasteners and an anvil section having an anvil for receiving the fasteners when advanced from the cartridge. The cartridge and anvil sections clamp tissue therebetween. A cam member is slidable within the cartridge section to fire the fasteners, and is movable from a first position defining a first distance from the anvil to a second position defining a second different distance from the anvil. A cam adjusting member is operably associated with the cam member and moves the cam member from the first position to the second position in response to a thickness of tissue clamped between the anvil and cartridge sections.