A noise cancelling device for detecting divergence of a coefficient of an adaptive filter without setting a threshold value in advance based on characteristics of a device from which noise is to be cancelled or an environment. The noise cancelling device includes: a divergence coefficient unit for obtaining a filter divergence coefficient from a filter coefficient of a section not including a filter coefficient at a basic tap position decided by the distance between a reference input unit and an audio input unit; a divergence threshold value calculation unit for obtaining a filter divergence threshold value from a filter coefficient of a section including the filter coefficient at the basic tap position; and a divergence detection unit for comparing the filter divergence coefficient to the filter divergence threshold value so as to detect the divergence condition of the adaptive filter.