A storage apparatus includes a flash memory that includes multiple blocks; and a control portion that reads data written in the block and writes the data into the block. The flash memory includes one block set having n pieces of the blocks including BR1 to BRn. A write data and a write flag are capable of being written into each of blocks BRi, the write data being written in accordance with a request, the write flag indicating that the write data has been written into a target block BRj. In accordance with a write request, the control portion performs an erasure process, a first write process, and a second write process. The erasure process erases the data including the write data and the write flag. The first write process writes the new write data into the block BRl. The second write process writes the write flag into a block BRm.