1. A resolution increasing apparatus that decodes encoded data of a motion image compressed by a motion image encoding system and generates a high-resolution image from an image after the decoding, the resolution increasing apparatus comprising: a provisional-high-resolution-image generating unit that sequentially sets images formed by the image after the decoding as a reference frame, generates, from the reference frame, a provisional high-resolution image having a number of pixels larger than that of the reference frame according to interpolation processing, sets a plurality of pixels included in the reference frame as a pixel of attention one by one, and acquires, based on the encoded data, predetermined encoded mode information for each pixel of attention or each specific range including the pixel of attention; a determining unit that determines, based on encoded mode information corresponding to the pixel of attention, whether correction to a pixel value of a corresponding position of the provisional high-resolution image equivalent to a position of motion 0 with respect to the pixel of attention is performed; a corresponding-point searching unit that acquires a corresponding point corresponding to the pixel of attention at decimal number accuracy out of the image after the decoding; and an image correcting unit that applies, when the determining unit determines that the correction for the pixel value of the corresponding position of the provisional high-resolution image is performed, predetermined correction processing to the pixel value of the corresponding position of the provisional high-resolution image and outputs, when the determining unit determines that the correction is not performed, the pixel value of the corresponding position of the provisional high-resolution image as a high-resolution image.