A cut-off circuit cuts off supply of a power supply voltage from a voltage supply circuit to a non-volatile memory block. A discharge circuit discharges an electric charge accumulated in stability capacitance. In a data retention test of the memory block, a self test circuit instructs the cut-off circuit to start operation after writing predetermined data into the memory block, and instructs the cut-off circuit to stop the operation to check retention of the predetermined data in the memory block in a predetermined time after the instruction to the cut-off circuit to start the operation. Further, in the data retention test of the memory block, the self test circuit instructs the discharge circuit to start operation along with the instruction to the cut-off circuit to start the operation, and instructs the discharge circuit to stop the operation along with the instruction to the cut-off circuit to stop the operation.