PURPOSE: To surely remove a high frequency noise without increasing the number of parts to be used in respect to a pulse signal processor for processing a pulse signal in which a high frequency noise is easily mixed.

CONSTITUTION: A CPU reads out the level of an input pulse signal in a certain sampling interval, compares the read data SP(n) with data SP(n-1) read in the preceding sampling interval, and when both the data coincide with each other, the data SP(n) read in the current sampling interval are defined as output data DATA(N). In the case of discordance, the output data DATA(n-1) of the preceding sampling period are defined as output data DATA(n).