An echo cancelling device splits a low-band signal through LPFs having characteristics which do not cause aliasing during downsampling of downsamplers, and splits a high-band signal through HPFs having characteristics which do not cause aliasing during downsampling of downsamplers. The echo canceling device generates a mid-band signal by subtracting the low-band signal and the high-band signal from a pre-split signal by adder-subtractors, and cancels an echo on a band-by-band basis.