A pixel interpolating device using the IM-GPDCT method and capable of preventing noise generation divides an original image into a plurality of blocks and picks up a block to be processed as a target block. Further, an image peripheral to the target block is extracted as a peripheral image. By using the peripheral image as an extension region, DCT transform is carried out. Thereafter, the peripheral image is magnified, and the IM-GPDCT processing is carried by using the magnified image.