PROBLEM TO BE SOLVED: To enable a pitch period extracting method by a plurality of window widths even in a device provided with an inexpensive DSP or CPU with a low calculation capacity.SOLUTION: A pitch period extracting device 100 includes: a calculation processing section load stabilizing index calculation section 130 that calculates the number of running processes or a total value of weights of the running processes, etc. as a load amount; a plural window widths and number thereof determination section 140 that determines the number of analysis windows N(P) so that the number of the analysis windows N(P) decreases if a load of calculation processing is high, and the number of the analysis windows N(P) increases if the load of calculation processing is low; and a pitch period extracting section 110 performs autocorrelation analysis processing for the number of the analysis windows N(P) determined by the plural window widths and number thereof determination section 140 to extract a pitch period. Since the n
