IMAGE COMPRESSING DEVICE AND IMAGE COMPRESSING METHOD

A prefetched-image memory stores a prefetched image of a prefetched area prefetched from a reference image memory that stores a reference image. A processor performs a motion search using a reduced image obtained by reducing an encoding target image and generates a search result for an encoding target block included in the encoding target image. The processor determines, based on the search result, that an area situated outside the prefetched area in the reference image is to be searched when the processor has predicted from the search result that a matching of the encoding target block and the prefetched image will be unsuccessful. Next, the processor performs a matching of the encoding target block and an image of a matching target area including the outside area in the reference image and generates an inter-prediction result. Then, the processor encodes the encoding target block based on the inter-prediction result.