A stapling head assembly, and said stapling head assembly comprises: a cartridge support, equipped detachably with a cartridge and comprising a first limiting groove along the longitudinal direction thereof; an actuating block with an unlocking component, set movably in said cartridge; a cutter, movable at least between a first position and a second position along the longitudinal direction of said cartridge support, wherein, when said cutter moves from the first position distally to the second position, said actuating block is pushed to move by said cutter, so that said cutter and said actuating block move along said first limiting groove; two lockout mechanisms at two sides of said first limiting groove, wherein each lockout mechanism comprises: a lockout block, set in said cartridge support, and movable between a third position and a fourth position along the transversal direction of said cartridge support relative to said cartridge support; a flexible component, set between said cartridge support and said lockout block, and actuating said lockout block to move from said third position to said fourth position towards said first limiting groove; before said actuating block being actuated to move by said cutter, and when said cutter is located at the first position proximal to the lockout blocks, said unlocking component squeezes said lockout blocks transversally to be at said third position, and keeps said flexible components under compression status, such that said cutter can move from said first position to said second position to actuate the actuating block; after the actuating block being actuated to move by said cutter, when said actuating block remains at a distal end of the cartridge, and when said cutter is reset to the first position, said lockout blocks are moved to said fourth position under the action of said flexible components, such that the space between said lockout blocks is smaller than the transversal thickness of said cutter and said cutter is prevented from moving from said first position to said second position by said lockout blocks. a cartridge support, equipped detachably with a cartridge and comprising a first limiting groove along the longitudinal direction thereof; an actuating block with an unlocking component, set movably in said cartridge; a cutter, movable at least between a first position and a second position along the longitudinal direction of said cartridge support, wherein, when said cutter moves from the first position distally to the second position, said actuating block is pushed to move by said cutter, so that said cutter and said actuating block move along said first limiting groove; two lockout mechanisms at two sides of said first limiting groove, wherein each lockout mechanism comprises: a lockout block, set in said cartridge support, and movable between a third position and a fourth position along the transversal direction of said cartridge support relative to said cartridge support; a flexible component, set between said cartridge support and said lockout block, and actuating said lockout block to move from said third position to said fourth position towards said first limiting groove; a lockout block, set in said cartridge support, and movable between a third position and a fourth position along the transversal direction of said cartridge support relative to said cartridge support; a flexible component, set between said cartridge support and said lockout block, and actuating said lockout block to move from said third position to said fourth position towards said first limiting groove; before said actuating block being actuated to move by said cutter, and when said cutter is located at the first position proximal to the lockout blocks, said unlocking component squeezes said lockout blocks transversally to be at said third position, and keeps said flexible components under compression status, such that said cutter can move from said first position to said second position to actuate the actuating block; after the actuating block being actuated to move by said cutter, when said actuating block remains at a distal end of the cartridge, and when said cutter is reset to the first position, said lockout blocks are moved to said fourth position under the action of said flexible components, such that the space between said lockout blocks is smaller than the transversal thickness of said cutter and said cutter is prevented from moving from said first position to said second position by said lockout blocks.