The utility model belongs to the class of stationary and office supplies. The utility model introduces for solving the problems that hand is easy to be hurt when a pencil is cut, pencil core is easy to break when the pencil is cut by a pencil sharpener, and the nib of the pencil is not durable because of the large taper of the pencil core. The planing blade for sharpening a pencil provided by the utility model is composed of a planing blade body and a blade. The blade is installed in a clearance hole on the back part of a long slot of the planing blade body, and the cutting edge of the blade is a little higher than the bottom surface of the long slot. While in use, a pencil to be planed is pulled in the long slot, and the planed taper of the pencil can be controlled by hand. As is shown in test, the utility model has convenient, simple structure and convenient popularization.