A digital-to-analog converting device comprises a signal processing circuit supplied with a discrete digital signal x.sub.n at a time nT, where n is a natural number and T is a sampling period, for converting the discrete digital signal x.sub.n into a digital signal y.sub.n satisfying an equation ##EQU1## where N is a natural number greater than i, a digital-to-analog converter for converting the output digital signal y.sub.n of the signal processing circuit into an analog signal having a continuous amplitude, and an analog lowpass filter supplied with the output analog signal of the digital-to-analog converter, for eliminating frequency components substantially equal to or higher than 1/2 a sampling frequency F.sub.s of the discrete input digital signal of the signal processing circuit.