IC CARD

PURPOSE:To omit a malfunction even when a control signal is unstable or a noise comes into a power source terminal by providing a writing terminal to supply a power to execute conversion to a high voltage with a voltage boosting circuit separately from the supplying terminal of a power source for the operation of a memory element. CONSTITUTION:An EEPROM 20 to have the voltage boosting circuit 21 is incorporated and separately from power source supplying terminals Vcc and Vss of this EEPROM 20, a writing terminal WT is provided to supply a power to the voltage boosting circuit 21. Then, the prescribed voltage is impressed to the writing terminal WT as needed, the writing and erasing of the EEPROM 20 are controlled and the erroneous writing is prevented. Thus, even when the control signal is unstable or the noise comes into the power source terminal, the reliability of an IC card can be improved much more.