PURPOSE: To provide the evaluation method of a signal versus noise ratio characteristic of a converter for a voice signal and an acoustic signal that is significant based on a human audible sense.

CONSTITUTION: The method is an evaluation method in which an input signal of a sine wave or its equivalent is given to a measured system as its input signal, a band pass filter 103 having a critical band width filters an output of the measured object to obtain a level of its output signal thereby obtaining an objective evaluation value in matching with a human audible sense. Furthermore, it is avoided that a word length of a measured system 102 is insufficient for the measurement of a narrow band noise characteristic of the measured system 102 by using a sine wave in which a noise component is shaped for the input signal.