A non-volatile memory device includes a memory cell array including memory cells, each having a resistance value reversibly transitioning among resistance value ranges, a read circuit that, in operation, obtains pieces of resistance value information each relating to the resistance value of one of the memory cells, an arithmetic circuit that, in operation, calculates a binary reference value based on at least a part of the pieces of resistance value information, and a write circuit. In operation, the read circuit selectively assigns, based on the binary reference value, one of two values to each of the pieces of resistance value information. In operation, the write circuit performs a first write operation on a memory cell corresponding to one of the two values among the memory cells.