PURPOSE: To provide a filtering device which can satisfactorily extract only the desired component such as noise removal.

CONSTITUTION: In the filtering device, an input signal is successively delayed by plural delay means 11a, 11b, 11c...11n, coefficients are multiplied to the input signal and the outputs of the respective delay means by respectively different coefficient multipliers 12a, 12b, 12c...12n+1, the outputs of these respective coefficient multipliers 12a-12n+1 are added, and the desired component of the input signal is extracted. Concerning such a filtering device, the difference of the input signal is detected by a difference detection circuit 2, the coefficients of the respective coefficients multipliers 12a-12n+1 are set based on this detected difference, and the setting of coefficients based on this difference is performed by using linearly approximated functions.