To obtain an excellent edge enhancement effect even when dynamic .gamma. correction processing is executed for an edge-enhanced image signal, and to obtain an excellent edge enhancement effect for various .gamma.-characteristics. An edge component is detected from an input image signal. A .gamma. correction curve is calculated based on characteristics of an image scene detected by a scene characteristic detector, and its data is stored in a dynamic .gamma. correction RAM table and an inverse gradient RAM table. A gain controller multiplies the edge component by a control signal from the inverse gradient RAM table to generate an edge enhancement signal which is in turn added to the image signal to obtain an edge-enhanced signal. The inverse gradient RAM table sends an inverse number of a gradient of a .gamma. correction curve corresponding to a signal level of the inputted image signal as the control signal to the gain controller. An edge-enhanced signal becomes an image signal for which dynamic .gamma. correction is performed in accordance with a dynamic .gamma. correction RAM table to be outputted.