PURPOSE: To make an LSI of a device to reduce the size and the cost by providing a parallel-serial converting circuit, a selecting circuit, and a serial-parallel converting circuit as digital circuits and selecting and outputting M signals out of N input signals to be selected in accordance with the precedence.

CONSTITUTION: A parallel-serial converting circuit 10 converts N parallel signals X1 to XN to be selected to serial signals, and a selecting circuit 20 selects and outputs M signals out of the serial output signals to be selected from the parallel-serial converting circuit 10 in accordance with the precedence. The output serial signals of the selecting circuit 20 are converted to parallel signals by a serial-parallel converting circuit 30, and M selected signals Y1 to YM are outputted in parallel. Thus, the device is made into an LSI because all circuits consist of digital circuits without using a ROM, and consequently, the size and the cost of the device are reduced.