PURPOSE: To obtain a complete random number, by obtaining an initial data from a random number source every time when a random number group is generated.

CONSTITUTION: A timepiece memory 5 is alloted at a prescribed region of a memory 1, and the timepiece data given from a timepiece mechanism 4 is rewritten momentarily to the memory 5. Accordingly the timepiece data of the memory 5 has a change at all times, and as a result the timepiece data which are fetched during the execution of a random number producing program are virtually regarded as random numbers. In such way, the timepiece data is used as the initial value of the random number when the random number producing program is executed. Thus the correlation function is extremely diluted for each random number group.