The present invention relates to an image processing device including pixel interpolation, such as a pixel interpolation device, a line interpolation device, an image size conversion device and an image interpolation device.The pixel interpolation device according to the present invention includes an interpolation pattern table, which outputs an interpolation direction data designating interpolation directions including directions joining intermediate points of pixels. The interpolation pixel data is calculated based on the pixel data located in the interpolation direction designated by the interpolation direction data. The image interpolation device, the pixel number conversion device and the line interpolation device according to the present invention includes the pixel interpolation device described above.