A filter device comprising: a plurality of delay units (1-1 to 1-N) connected in series to delay an input signal in response to reception of the input signal and to respectively output a respective delayed signal; a plurality of multiplication units (2-0 to 2-N) to multiply the delayed signals respectively output from the delay units (1-1 to 1-N) by respective filter coefficients having a representation range having a maximum value, the filter coefficients being respectively generated based on respective multiplication results obtained by multiplying respective predetermined design values by a multiplying factor adjustment value; a coefficient adjustment unit to, when a multiplication result obtained by multiplying a predetermined design value by the multiplying factor adjustment value exceeds the maximum value of the representation range of the filter coefficient generated based on said multiplication result, divide the multiplication result exceeding the maximum value by the maximum value, output a quotient of the division as a coefficient adjustment value, wherein, when a multiplication result obtained by multiplying a predetermined design value by the multiplying factor adjustment value exceeds the maximum value of the representation range of the filter coefficient generated based on said multiplication result, then a remainder obtained by dividing the multiplication result by the maximum value is utilized as the filter coefficient generated based on said multiplication result, else, the multiplication result is utilized as the filter coefficient generated based on said multiplication result; a signal conversion unit to output a signal obtained by adding after-filter-coefficient-multiplication signals output by the plurality of multiplication units (2-0 to 2-N) and an adjusted signal obtained by adjusting a corresponding delayed signal using the coefficient adjustment value, wherein adjusting the corresponding delayed signal using the coefficient adjustment value comprises multiplying the corresponding delayed signal by the coefficient adjustment value or performing an addition of instances of the corresponding delayed signal, said instances being equal in number to the coefficient adjustment value; and a division unit to generate an output signal by dividing the signal output by the signal conversion unit by the multiplying factor adjustment value. a plurality of delay units (1-1 to 1-N) connected in series to delay an input signal in response to reception of the input signal and to respectively output a respective delayed signal; a plurality of multiplication units (2-0 to 2-N) to multiply the delayed signals respectively output from the delay units (1-1 to 1-N) by respective filter coefficients having a representation range having a maximum value, the filter coefficients being respectively generated based on respective multiplication results obtained by multiplying respective predetermined design values by a multiplying factor adjustment value; a coefficient adjustment unit to, when a multiplication result obtained by multiplying a predetermined design value by the multiplying factor adjustment value exceeds the maximum value of the representation range of the filter coefficient generated based on said multiplication result, divide the multiplication result exceeding the maximum value by the maximum value, output a quotient of the division as a coefficient adjustment value, a signal conversion unit to output a signal obtained by adding after-filter-coefficient-multiplication signals output by the plurality of multiplication units (2-0 to 2-N) and an adjusted signal obtained by adjusting a corresponding delayed signal using the coefficient adjustment value, wherein adjusting the corresponding delayed signal using the coefficient adjustment value comprises multiplying the corresponding delayed signal by the coefficient adjustment value or performing an addition of instances of the corresponding delayed signal, said instances being equal in number to the coefficient adjustment value; and a division unit to generate an output signal by dividing the signal output by the signal conversion unit by the multiplying factor adjustment value.