A speech decoding device adapted for decoding an encoded speech signal, the speech decoding device comprising: bit stream separating means adapted for separating a bit stream that includes the encoded speech signal into an encoded bit stream and temporal envelope supplementary information, the bit stream received from outside the speech decoding device; core decoding means adapted for decoding the encoded bit stream separated by the bit stream separating means to obtain a low frequency component; frequency transform adapted for transforming the low frequency component obtained by the core decoding means into a frequency domain; high frequency generating means adapted for generating a high frequency component by copying the low frequency component transformed into the frequency domain by the frequency transform means from a low frequency band to a high frequency band; high frequency adjusting means adapted for adjusting the high frequency component generated by the high frequency generating means to generate an adjusted high frequency component; low frequency temporal envelope analysis means adapted for analyzing the low frequency component transformed into the frequency domain by the frequency transform means to obtain temporal envelope information; supplementary information converting means adapted for converting the temporal envelope supplementary information into a parameter for adjusting the temporal envelope information; temporal envelope adjusting means adapted for adjusting the temporal envelope information obtained by the low frequency temporal envelope analysis means to generate adjusted temporal envelope information, the temporal envelope adjusting means using the parameter in said adjusting the temporal envelope information; and temporal envelope shaping means adapted for shaping a temporal envelope of the adjusted high frequency component, by multiplying the adjusted high frequency component by the adjusted temporal envelope information, bit stream separating means adapted for separating a bit stream that includes the encoded speech signal into an encoded bit stream and temporal envelope supplementary information, the bit stream received from outside the speech decoding device; core decoding means adapted for decoding the encoded bit stream separated by the bit stream separating means to obtain a low frequency component; frequency transform adapted for transforming the low frequency component obtained by the core decoding means into a frequency domain; high frequency generating means adapted for generating a high frequency component by copying the low frequency component transformed into the frequency domain by the frequency transform means from a low frequency band to a high frequency band; high frequency adjusting means adapted for adjusting the high frequency component generated by the high frequency generating means to generate an adjusted high frequency component; low frequency temporal envelope analysis means adapted for analyzing the low frequency component transformed into the frequency domain by the frequency transform means to obtain temporal envelope information; supplementary information converting means adapted for converting the temporal envelope supplementary information into a parameter for adjusting the temporal envelope information; temporal envelope adjusting means adapted for adjusting the temporal envelope information obtained by the low frequency temporal envelope analysis means to generate adjusted temporal envelope information, the temporal envelope adjusting means using the parameter in said adjusting the temporal envelope information; and temporal envelope shaping means adapted for shaping a temporal envelope of the adjusted high frequency component, by multiplying the adjusted high frequency component by the adjusted temporal envelope information,