PURPOSE: To correctly and accurately record a data by making a data invalid when a data memory is full before a series of data to be recorded in the data memory are all recorded.

CONSTITUTION: A CPU 3 of an IC card 1 reads a recording data stored in an internal memory and writes in a data memory 4. Whether the written data in the data memory 4 is correct or not is checked by reading the data and referring the recording data in the internal memory and when all the recorded data is recorded in the data memory 4, a normal signal is outputted to a CPU 11 of an IC card treating machine 10. When a part of the recorded data is not recorded in the data memory 4, an invalid flag is recorded in an invalid flag recording area (b) of the data memory 4 and an abnormal signal is outputted to the CPU 11.