The invention provides a differential type taper hole knife rest. The differential type taper hole knife rest is provided with a knife rest guide rail [18], wherein the knife rest guide rail [18] and a boring rod [8] form an included angle; the knife rest guide rail is arranged on a moveable knife rest; a screw rod [20] and the guide rail are arranged on the boring rod in parallel; the moveable knife rest is in threaded connection with the screw rod; a gear [6] is fixedly arranged at one end of the screw rod; a moveable gear [14], a fixed gear [5] and the boring rod are coaxially arranged; a gear shaft [11] and the boring rod are arranged on a boring equipment frame in parallel; two driving gears [13] which are fixedly connected with each other mutually are arranged on the gear shaft; the two gears are meshed with the fixed gear and the moveable gear respectively; the two pair of meshed gear groups have different gear ratio; and the moveable gear is meshed with the gear on the screw rod. Compared with the prior art, the differential type taper hole knife rest has the advantages that the knife feeding is driven by rotation of the boring rod, the moveable knife rest is moved along with the rotation of the boring rod, continuous knife feeding is realized, and the boring precision is improved.