Disclosed is an edge sharpening method using maximum and minimum filters. In an embodiment of the present invention, the edge region of an input image signal is detected, minimum and maximum signals are generated for the detected edge region, the input signal of the detected edge region is compared with the average signal of the minimum and maximum signals, and the average of the input signal and the maximum signal is output if the input signal is larger than the average signal, the average of the input signal and the minimum signal is output if the input signal is smaller than the average signal, and the input signal is output if the input signal is equal to the average signal. Meanwhile, median filtering, using a window perpendicular to the direction in which the edge sharpening is performed, is performed on the region on which the edge sharpening has been performed.