In super-resolution processing in which a plurality of low resolution images are synthesized to generate a high resolution image, a high-quality high-resolution image is to be generated with suppression of the noise ascribable to motion estimation error. Motion estimating means 11 estimates motion of pixels between a basis image selected out of plural low resolution images and remaining reference images, and outputs a result of motion estimation. Motion estimation reliability evaluating means 12 evaluates reliability of the result of motion estimation output from the motion estimating means 11, based on such as analogy in luminance of pixels, correlated by the results of the motion estimation, and outputs a motion estimation reliability value indicating the degree of reliability. High resolution image estimating means 16 synthesizes the respective pixels of the input low resolution images with weighting conforming to the motion estimation reliability value output from the motion estimation reliability evaluating means 12 to generate a high resolution image.