An echo sound signal suppressing apparatus for suppressing an echo sound signal to ensure speech communication between a far-end speaker and a near-end speaker, comprising: first power value calculating means for calculating the power value of the second sound signal; second power value calculating means for calculating the power value of the echo replica sound signal produced by the echo replica sound signal producing means; echo sound suppressing means for suppressing the echo sound difference signal component outputted from the difference signal producing means to a minimum level with the power value of the second sound signal calculated by the first power value calculating means and the power value of the echo replica sound signal calculated by second power value calculating means with the near-end speaker sound signal component being allowed to pass therethrough, the echo sound suppressing means having an output terminal to the communication line to output the near-end speaker sound signal component under the condition that the echo sound signal component is reduced to its smallest level.