The invention relates to a surgical stapler for applying at least two rows of staples, said surgical stapler comprising a
cartridge housing said rows of staples and having a slot extending along the
cartridge between two rows of staples, said surgical stapler further comprising a
cutting means movable along said slot and a
lockout mechanism for preventing movement of said
cutting means, wherein said
lockout mechanism comprises a blocking member movable between a first position, in which the blocking member blocks movement of said
cutting means, and a second position, in which the blocking member permits movement of said cutting means, and a biasing member for biasing said blocking member towards said first position and wherein said
cartridge comprises a release member for moving said blocking member towards said second position upon
insertion of said cartridge into said surgical stapler.