A linear surgical stapler includes an upper staple cartridge receiving half-section, a lower staple cartridge receiving half-section and a staple cartridge assembly. The staple cartridge assembly includes a cutting groove in which a reciprocating movement cutter is mounted. The cutter includes a bottom surface and a knife blade located at a far end of the cutter. The staple cartridge assembly includes a restricting member mounted therein and an elastic stopper. The elastic stopper abuts against the restricting member when the staple cartridge assembly is in an initial state. The restricting member breaks away from the staple cartridge assembly when the staple cartridge assembly is in a firing complete state, thereby preventing the cutter from sliding towards the far end of the staple cartridge. As a result, misfiring throughout the whole operation of the linear surgical stapler is prevented.