An image reading method and an image expansion method are provided whereby a low-resolution imaged picture can be expanded to have a high image quality even if an input image sequence is motionless, that is to say, even if a subject is motionless. An image expansion device has an image input unit, which shoots an input image, a reading position determination unit, which determines the reading position of a mixed image and a decimated image, an image reading unit, which reads the mixed image and the decimated image at the reading position from the input image, a positioning unit, which positions a plurality of mixed images to calculate a motion vector indicating the amount of displacement among the images, a displacement compensation unit, which compensates for the motion vector based on the amount of movement of the reading position, and an image expansion unit, which uses a plurality of decimated images to perform super-resolution reconstruction, based on the post-compensation motion vector, and expands the image.