To reduce the maximum value and the average of the number of bits which change at the sometime, in the transmission of a logical signal.

This device is equipped with a logical circuit 100, which converts a logical signal of n bits into m pairs (m is an integer equal to one or larger) of a group of logical signals, where only k bits (k is an integer equal to one or larger) change, a transmission line for transmitting the m pairs of logical signals, where only the k bits change, and a logical circuit 103 which converts the m pairs of logical signals, where only k bits change into a logical signal of the original n bits. Thus, for the maximum value of the number of changing bits has the product of k and m as an upper limit. Also, when the product of k and m is less than n/2, the average number of changing bits can be reduced also.