In order to enable a rewrite of stored data to be omitted and to reduce a processing time of error concealment even if an error is detected in a process for sequentially storing variable-length data in a memory and the rewrite of the stored data is necessary, variable-length data from which an error is not detected is sequentially stored at and after a predetermined position in the memory, and error information that includes a restoration address that corresponds to an area in which variable-length data from which an error is detected is to be stored and that specifies variable-length data stored earliest in the memory from among data to be replaced with error concealment data is stored at a position preceding the predetermined position, when the error is detected.