According to an embodiment, a row decoder to perform row decoding by using, as row soft input information, a row received word read as soft determination information from a non-volatile memory and to calculate row extrinsic information and a column decoder to perform column decoding by using column soft input information, which is a result of adding of the row extrinsic information to a column received word read as soft determination information from the non-volatile memory, and to calculate column extrinsic information are included. The row decoder includes a first decoder for first decoding, a second decoder for second decoding a decoding method of which is different from that of the first decoding, and a selection unit to select a decoded result based on accuracy of a decoded result of the first decoding and that of a decoded result of the second decoding and to calculate the row extrinsic information.