To provide a tone detection device and its detection method that has higher frequency and time resolution than before regardless of a simple configuration.

A tone signal detection part 10 uses a band elimination filter to a filter processing part 12a of a band-adaptive control part 12 of a signal 16 to be supplied, further updates a coefficient used by the filter with a new coefficient being generated by adaptive control using a coefficient control part 12b, and uses the updated coefficient for minimizing an output signal at a given band being outputted from the filter processing part 12b. A tone decision part 14 compared the power ratio and a predetermined threshold between the input signal 16 and a minimized output signal 20 and outputs an output signal 24 where it has been to be a tone signal when the power ratio is equal to or less than the predetermined threshold.