A management controller controls a data buffer and a flash controller, which controls I/O of data to and from flash memories, based on a search request. A data decompression engine includes a plurality of data decompression circuits for decompressing, in parallel, the compressed data transferred from the data buffer. A data search engine includes a plurality of data search circuits for searching, in parallel, data which satisfies search conditions among the respective data that were decompressed by the data decompression circuits, and transfers, to the search request source, the data obtained in the search performed by the data search circuits, wherein the flash controller reads, in parallel, a plurality of compressed data requested in the search request, and transfers the read compressed data to the data buffer, and the management controller transfers the compressed data to the data decompression engine when the compressed data is stored in the data buffer.