The gradients of a reference image signal and suppression target image signals are respectively detected. Suppression coefficients are computed according to functions defined based on the magnitude relationship among the gradient value of the reference image signal and those of the suppression target image signals. The reference image signal is weighted according to the suppression coefficients, the weighted signals are combined with the corresponding suppression target image signals, and the combined signals are output as color component signals after color fringing suppression. Then, color fringing can be effectively corrected while suppressing correction errors.