This application provides a linear stapler with an adjusting mechanism having wider adjusting scope and more suitable pressing force and being more convenient to operate, and including an adjusting shift lever with at least one step surface on each of upper and lower ends, an adjusting slider with multiple step surfaces on an end surface close to the adjusting shift lever, and an adjusting chassis having multiple step surfaces on an end surface close to the adjusting shift lever. The adjusting shift lever rotates with a shifted adjusting knob to generate relative displacement vertical to the step surface with the adjusting slider at one end and relative displacement vertical to the step surface with the adjusting chassis at the other end, and drive a nail abutting seat subassembly to rotate relatively to a nail bin seat, until the thickness of clamped tissue is consistent in near and far ends.