In the sound insulation apparatus, a sound wave transmitter configured to transmit sound waves with frequencies including the frequencies of propagation sound waves from a sound source and a sound wave receiver configured to receive the sound waves transmitted from the sound wave transmitter are coupled such that the orientation of a sound wave transmission surface of the sound wave transmitter and the orientation of a sound wave receiving surface of the sound wave receiver intersect each other and one pair set is formed. The one pair set is disposed in plurality such that the sound wave transmission surface of one set is spaced from and opposed to the sound wave receiving surface of another set and a space surrounding the sound source is formed. The sound waves transmitted from each of the sound wave transmitters are mixed with the propagation sound waves.