An edge emphasizing circuit includes a first high-frequency detection circuit and a second high-frequency detection circuit. A spatial frequency of a raw image signal corresponding to a photographed object is detected by the first high-frequency detection circuit or the second high-frequency detection circuit, and a gain corresponding to a detection result is made effective. The gain to be made effective is decreased as the spatial frequency of the raw image signal is low. The gain is applied to an edge emphasizing signal generated by the edge emphasizing circuit, and the raw image signal is added to the edge emphasizing signal to which the gain is applied. Thus, a raw image signal with an emphasized edge is obtained.