PURPOSE: To lengthen the life of a kitchen knife even in the case where the grinding operation is repeated many times by performing the grinding operation in such a manner as to decrease the cutting amount of the knife root than that of the knife edge.

CONSTITUTION: A kitchen knife support base 13 is disposed on the upper surface of a kitchen knife driving table 10 freely reciprocated parallel to the rotating surface of a grinding wheel 5, and an energizing spring, the energizing force of which is changed by a pressure control cylinder, is disposed to energize the kitchen knife support base 13 toward the grinding wheel 5. A kitchen knife support table 14 for holding a designated kitchen knife 20 is disposed on the kitchen knife support base 13 in such a manner as to be freely rotated in the horizontal direction by a rotation cylinder, and as the grinding position of the kitchen knife 20 is moved from the knife root to the knife edge, the energizing force of the energizing spring is increased. The cutting amount of the knife edge is increased by turning the kitchen knife support table 4.