Abstract: The invention relates to a chipper knife with at least one cutting edge (6) along at least one of its side edges. The chipper knife is adapted to be mounted in chippers of the kind which are used to cut chips of a desired size and shape from pieces of wood or timber (7) and which comprise a tool, in the form of a plane or conical disc, which is arranged for rotation about an axis of rotation and on which a plurality of such chipper knifes (2) are mountable in such manner that one end of the cutting edge of the chipper knife is located closer to the axis of rotation of the tool than the opposite end of the cutting edge. The cutting edge (6) of the chipper knife is formed between a timber-guiding surface and a chip-guiding surface, the timber-guiding surface having a varying angle along its length in relation to a plane of rotation in such a way that the angle is greater at the end of the cutting edge located closest to the axis of rotation decreases in the outward direction.