To precisely grind a kitchen knife along a knife-edged shape by providing a pair of left and right grinding wheels for grinding to grind a blade surface by rotating while elastically holding a placing base furnished with a pair of left and right knife holding members and the blade surface of the knife from both sides.

Grinding treatment is carried out extremely simply and in a short period of time only by inserting a kitchen knife 20 in a state where a blade is vertically erected on the upper surface side from an edge by actuating a motor 7 and moving the knife 20 in the longitudinal direction. At this time, the knife 20 is elastically held from both sides by knife holding members 2, 2 and is in a stable state. Additionally, a blade surface is also elastically held from both sides by grinding wheels 3, 3 for grinding and is in a close contact state. Consequently, it is possible to apply high precision grinding. Additionally, it is possible to carry out high precision grinding even on any knives of any shapes by changing the knife holding members 2, 2 and the grinding wheels 3, 3 for grinding to the most suitable ones in accordance with a shape of the knife 20.