An image processing method comprising a step of performing a color interpolation process on image data output from a single-chip color image capturing sensor to calculate color data for each pixel and a step of converting the color data using a predetermined transformation formula and of filtering the converted data, and the transformation formula is replaced based on the magnitude of a color value of the color data. When a color value of a specific color is large, the transformation formula can be appropriately changed. Therefore, it is possible to prevent the lowering of the overall resolution without being affected by the resolution of the color. Further, it is possible to reliably reproduce a smooth and natural edge of an image without adding other processes to the color interpolation process.