Abstract: A memory card device and method of rewriting the same which require no separate memory for saving all data in a chip containing data to be rewritten, and in which data are not lost due to a power source failure that may occur during writing operation. Each of a plurality of chips which constitute a memory card is provided with; a logic address, a control region containing a write start number and a write completion number, and a data region. An erased chip is prepared within the memory card device. A write start number in a chip containing data to be rewritten is written, for example, into the erased chip by performing incrementing operation. Data in the data region which is not to be rewritten in a chip containing data to be rewritten are copied into the erased chip and new rewrite data are written into the erased chip. A write completion number in the chip containing data to be rewritten is written, for example, into the erased chip by performing incrementing operation on the write completion number.