A post-processing circuit for processing an image signal according to frequency components of an image signal includes: a low-frequency extracting unit outputting a low-frequency image component of the image signal as a low-frequency signal; a high-frequency extracting unit multiplying a high-frequency image component of the image signal by a first gain and outputting the multiplication product as a high-frequency signal; an intermediate-frequency extracting unit multiplying an intermediate-frequency image component of the image signal by a second gain and outputting the multiplication product as an intermediate-frequency signal; and an adder adding the low-frequency signal, the high-frequency signal, and the intermediate-frequency signal and outputting the addition sum as a post-processed signal, wherein the first gain and the second gain are differently set according to a pixel location in a spatial domain.