A decoding device according to an embodiment includes: a reception memory for storing received image; a frame buffer for storing a reference image; a decoding unit for decoding the received image based on the reference image stored in the frame buffer; a reference image storage for storing the decoded image, decoded by the decoding unit, in the frame buffer as the reference image; and an output image selection unit for selecting the reference image stored in the frame buffer as an output image when the reception memory underflows and selecting the decoded image as the output image when the reception memory does not underflow.