A non-volatile semiconductor storage device includes a memory cell array having plural electrically rewritable memory cells, each memory cell including a variable resistive element storing resistance values as data in a non-volatile manner, and a data writing unit having a voltage supply circuit which supplies a voltage needed to write data to the plural memory cells, and a resistance state detecting circuit which detects a resistance state of the variable resistive element at the time of writing the data. The data writing unit stops the supply of the voltage to the memory cell where a resistance state of the variable resistive element becomes a desired resistance state, among the plural memory cells, according to the detection result of the resistance state detecting circuit.