PURPOSE: To access a data base without noticing the structure of the data base by reading out data from the data base on the basis of a converted access request and operating the read-out data on the basis of an arithmetic instruction.

CONSTITUTION: When an access code 30 is applied to an execution part 16, instructions are taken out one by one by an instruction counter (not shown in figure), whether each instruction is a calculation instruction or an access instruction is discriminated by an instruction distributing part 32 and one of an calculation instruction executing part 34 and an access instruction executing part 36 is started. When the instruction execution part 36 is started, an access instruction corresponding to the access method inherent to the data base to be accessed is applied to a data base control system 42. Records x, y read out in response to the access instruction are stacked in a data stack 38 and used as pointers at the access to records, so that the positions, size, etc. of these records on the data stack are stacked on a display stack 40.