PURPOSE: To make it possible to easily verify a ROM code number from outside even on the manufactured article on which resin has been sealed by a method wherein the first read-only memory, in which data and a program are stored, and the second read-only memory in which the code number of the first read- only memory is stored are provided.

CONSTITUTION: The first read-only memory, in which data and a program are stored, and the second read-only memory, in which the code number of the first read-only memory is stored, are provided on an integrated circuit containing a read-only memory. When the above mentioned second read-only memory is accessed from the exterior, said code number is made possible to be verified by reading out the code number to the exterior. For example, a region 0 in which the ROM code number is stored, is provided inside the ROM 4, a specific address of the ROM is assigned, and a program and data are stored in the remaining region 10 by the user. As a result, the ROM code number can be easily verified from outside the integrated circuit without conducting probing.