The cutting apparatus includes one motor, one gear train electrically connected to the motor, one protuberant unit connected to the gear train, one sliding block with one runner for the protuberant unit to be set in, one rotation shaft connected to the sliding block, one shifting assembly pivoted to the rotation shaft and one cutting assembly. When the protuberant unit is driven by the gear trainto rotate, the sliding block moves synchronously to limit the protuberant unit inside the runner and the protuberant unit reciprocates linearly inside the runner, so that the cutting assembly completeslinear cutting.