PURPOSE: To make it possible to take out pseudo random number data simply in a high speed, by outputting storage data of an ROM as pseudo random numbers to the external by a program.

CONSTITUTION: When program counter 5 starts address designation of program area 4 of ROM 2, data counter 6 designates addresses of control program area 3. Next, shifter 9 stores program data of area 3 read by indication of counter 6 and shifts this data serially by clock signal and supplies this serial data as pseudo random number data to port 10. Pseudo random number data taken out from port 10 is supplied to speaker 11. As a result, the imitation sound of game apparatus and so on can be obtained. By this constitution, the constitution is simplified in comparison with the generator using the independent random number table, and random numbers can be generated in a high speed by controlling the data generating timing.