Nonvolatile semiconductor memory device achieving shorter erasure time

摘要

A nonvolatile semiconductor memory device (10) includes a memory cell array (17), a control circuit (12) which repeatedly performs an automatic erasure operation with respect to an entirety of the memory cell array (17), the automatic erasure operation including a preparatory write operation prior to an erasure operation and a following erasure operation, and a counter (24) which counts how many times the automatic erasure operation is performed with respect to the entirety of the memory cell array (17), wherein the control circuit (12) stops the automatic erasure operation in response to an event that the counter (24) counts a desired number.