An effort-saving stapler includes a shell, a magazine, a hammer, an elastic element, a block, a trigger and an extensive element. The magazine is disposed in the shell for supporting and feeding nails. The hammer is disposed in the shell for hammering the nails, one at a time. The elastic element is disposed in the shell for biasing the hammer. The block is disposed in the shell. The trigger is movably and pivotally connected to the shell and engaged with the block at an engagement point. The extensive element includes a first end connected to the hammer and a second end telescopically connected to the trigger. When the trigger is operated, the hammer is lifted by the extensive element and the engagement point is moved towards the hammer.