PURPOSE: To protect an information data, and to prevent malfeasance by storing a level code different depending on the position or the qualification of individual person, on an ID card, and enabling data corresponding to the level code to be accessed.

CONSTITUTION: When an ID card 10 is inserted in a card reader 21, the ID code and the level code are read, then being sent to a processor 22. The processor 22 retrieves a code data memory 41 in a data base 40, and decides data memories 42, 43, or 44 possible to be accessed. Next, when a user inputs a prescribed password and a data request using a key pad 23, the processor 22 compares them with a corresponding password in the memory 41, and when they are coincided, the data is read out, and is outputted to a display 24, or a printer 30. Consequently, only the data required for a work can be accessed, thereby it is possible to protect a bit of data information, and to prevent the malfeasance.