To reduce an information amount which is transmitted and received, by maintaining sound quality in voice encoding and decoding of an analysis and synthesis type.

A voice encoding device expresses a residual signal created by applying prediction analysis to a voice signal, by a flag for indicating a noise band for the noise band, and by a frequency conversion coefficient for a non-noise band. The voice encoding device encodes the flag and the frequency conversion coefficient together with a prediction coefficient, and transmits it to a voice decoding device. The voice decoding device decodes a received code, and on the basis of a decoding result, a residual signal is restored by creation of a noise string and reverse conversion of the frequency conversion coefficient, and the voice signal is restored by inputting the residual signal to a filter section for synthesis, which is defined by the prediction coefficient.