NONVOLATILE SEMICONDUCTOR MEMORY DEVICE

According to an embodiment, a nonvolatile semiconductor memory device includes a nonvolatile memory, an ECC decoder, and a write controller. The nonvolatile memory includes a memory cell array and a buffer. The buffer is capable of storing page data read from the memory cell array and generating degeneration data by performing an exclusive OR operation on page data read from the memory cell array. The ECC decoder is capable of performing ECC decode on the degeneration data input from the nonvolatile memory and determining whether the degeneration data passes ECC decode or not. The write controller is capable of causing the nonvolatile memory to rewrite the plurality of page data when the degeneration data does not pass ECC decode.