There is provided a non-volatile memory which enables high accuracy threshold control in a writing operation. In the present invention, a drain voltage and a drain current of a memory transistor are controlled to carry out a writing operation of a hot electron injection system, which is wherein a charge injection speed does not depend on a threshold voltage. FIGS. 1A and 1B are views of a circuit structure for controlling the writing. In FIGS. 1A and 1B, an output of an operational amplifier 103 is connected to a control gate of a memory transistor 101, a constant current source 102 is connected to a drain electrode, and a source electrode is grounded. The constant current source 102 and a voltage Vpgm are respectively connected to two input terminals of the operational amplifier 103.