According to one embodiment, a memory system includes: a semiconductor memory including a memory cell array, the memory cell array including a memory cell, and a controller configured to issue a first read command sequence after a lapse of a first time period from access to the semiconductor memory, and issue a second read command sequence after a lapse of a second time period from access to the semiconductor memory. When the controller issues the first read command sequence, the semiconductor memory applies a first voltage and a second voltage to the memory cell. When the controller issues the second read command sequence, the semiconductor memory applies a third voltage and a fourth voltage to the memory cell.