A data generating device includes: a memory cell array including a plurality of memory cells; a read circuit operative to obtain a plurality of resistance value information pieces from the plurality of memory cells; and a data generator circuit operative to set a condition on the basis of the plurality of resistance value information pieces, and generating data by allocating, on the basis of the condition, the plurality of resistance value information pieces into a plurality of sets which respectively correspond to a plurality of values constituting the data. Each of the plurality of memory cells has a characteristic where, when in a variable state, a resistance value thereof reversibly changes between a plurality of variable resistance value ranges in accordance with an electric stress applied.