Signal inspection apparatus, signal inspection system, signal inspection method, and non-transitory computer-readable medium encoded with signal inspection program

A signal inspection apparatus, a signal inspection system, a signal inspection method, and a non-transitory computer-readable medium encoded with a signal inspection program are provided, all of which can appropriately detect discrepancy between multiplexed signals. A signal inspection apparatus includes: an acquisition unit that acquires values of at least two signals among multiplexed signals in a predetermined cycle; a count unit that counts respective changes in the at least two signals in a predetermined time frame; a calculation unit that calculates a difference between the counts of changes; and an output unit that performs an output indicating discrepancy between the signals, if the difference between the counts of changes exceeds an allowable value.