A kitchen knife with a sharpener, comprising: a knife blade having a cutting edge that is formed along a longitudinal edge of the knife blade, and a handle, into which a blade tang of the knife blade is inserted so as to be fixed, further comprising: a cutout recess formed in an end of the handle by cutting opposite lateral surfaces of the end of the handle so as to form a laid U-shaped cutout recess; a locking space formed in the handle in such a way that the locking space extends from an inside end of the cutout recess and defines a hollow chamber having a rectangular cross-section; and a sharpener, comprising: a locking part, a shank of which has a rectangular shape, the locking part being removably received in the locking space of the handle; characterized in that a sharpener body is extending from the locking part in the handle in such a way that an end bottom surface and opposite lateral surfaces of the sharpener body are exposed outside the handle; a whetting groove is transversely formed in the sharpener body; plate-shaped whetstones are inclinedly installed on opposing sidewalls of the whetting groove at predetermined inclination angles so that the whetstones form a V-shaped arrangement; and a rubber cushion is placed below a rear surface of the whetstone that is installed on at least one of the opposing sidewalls of the whetting groove. a cutout recess formed in an end of the handle by cutting opposite lateral surfaces of the end of the handle so as to form a laid U-shaped cutout recess; a locking space formed in the handle in such a way that the locking space extends from an inside end of the cutout recess and defines a hollow chamber having a rectangular cross-section; and a sharpener, comprising: a locking part, a shank of which has a rectangular shape, the locking part being removably received in the locking space of the handle; characterized in that a sharpener body is extending from the locking part in the handle in such a way that an end bottom surface and opposite lateral surfaces of the sharpener body are exposed outside the handle; a whetting groove is transversely formed in the sharpener body; plate-shaped whetstones are inclinedly installed on opposing sidewalls of the whetting groove at predetermined inclination angles so that the whetstones form a V-shaped arrangement; and a rubber cushion is placed below a rear surface of the whetstone that is installed on at least one of the opposing sidewalls of the whetting groove. a locking part, a shank of which has a rectangular shape, the locking part being removably received in the locking space of the handle; a sharpener body is extending from the locking part in the handle in such a way that an end bottom surface and opposite lateral surfaces of the sharpener body are exposed outside the handle; a whetting groove is transversely formed in the sharpener body; plate-shaped whetstones are inclinedly installed on opposing sidewalls of the whetting groove at predetermined inclination angles so that the whetstones form a V-shaped arrangement; and a rubber cushion is placed below a rear surface of the whetstone that is installed on at least one of the opposing sidewalls of the whetting groove.