A parameter decoding method comprising: a prediction residue decoding step of finding a quantized prediction residue vector based on encoding information included in a current frame of a speech encoded bit stream; and a parameter decoding step of decoding a parameter based on the quantized prediction residue vector, wherein, the prediction residue decoding step is characterized in that, when the current frame is erased, the quantized prediction residue vector in the current frame is calculated with the following formula x n j = β 0 j ⁢ x n + 1 j + ∑ i = 1 M β i j ⁢ x n - i j + β - 1 j ⁢ y n - 1 j where; β 0 j, β i j, β - 1 j: weighting coefficient of the quantized prediction residue of j'th component in a next frame, a past (i'th) frame, and weighting coefficient of a decoded line spectral frequency of j'th component in a preceding frame, x n j: the quantized prediction residue of j'th component in the current (n'th) frame, x n + 1 j: the quantized prediction residue of j'th component in the future (n+1'th) frame, x n - i j: the quantized prediction residue of j'th component in a past (n-i'th) frame, and y n - i j: a decoded line spectral frequency of j'th component in a past (n-1'th) frame wherein the weighting coefficients β 0 j, β i j, β - 1 j are obtained depending on moving average, MA, predictive coefficients α i j, α i ʹ j by solving to zero the following equation partially differentiated with respect to x n j D j = y n j - y n - 1 j 2 + y n + 1 j - y n j 2 y n j = ∑ i = 0 M α i j ⁢ x n - i j y n + 1 j = ∑ i = 0 M αʹ i j ⁢ x n + 1 - i j where y n j: a decoded line spectral frequency of j'th component in the current (n'th) frame, y n + 1 j: a decoded line spectral frequency of j'th component in the future (n+1'th) frame, α i j: j'th component of i'th-order component within MA predictive coefficient set in the current (n'th) frame, α i ʹ j: j'th component of i'th-order component within MA predictive coefficient set in the future (n+1'th) frame, and M: MA predictive order. a prediction residue decoding step of finding a quantized prediction residue vector based on encoding information included in a current frame of a speech encoded bit stream; and a parameter decoding step of decoding a parameter based on the quantized prediction residue vector, wherein, the prediction residue decoding step is characterized in that, when the current frame is erased, the quantized prediction residue vector in the current frame is calculated with the following formula x n j = β 0 j ⁢ x n + 1 j + ∑ i = 1 M β i j ⁢ x n - i j + β - 1 j ⁢ y n - 1 j β 0 j, β i j, β - 1 j: weighting coefficient of the quantized prediction residue of j'th component in a next frame, a past (i'th) frame, and weighting coefficient of a decoded line spectral frequency of j'th component in a preceding frame, x n j: the quantized prediction residue of j'th component in the current (n'th) frame, x n + 1 j: the quantized prediction residue of j'th component in the future (n+1'th) frame, x n - i j: the quantized prediction residue of j'th component in a past (n-i'th) frame, and y n - i j: a decoded line spectral frequency of j'th component in a past (n-1'th) frame wherein the weighting coefficients β 0 j, β i j, β - 1 j are obtained depending on moving average, MA, predictive coefficients α i j, α i ʹ j by solving to zero the following equation partially differentiated with respect to x n j D j = y n j - y n - 1 j 2 + y n + 1 j - y n j 2 y n j = ∑ i = 0 M α i j ⁢ x n - i j y n + 1 j = ∑ i = 0 M αʹ i j ⁢ x n + 1 - i j y n j: a decoded line spectral frequency of j'th component in the current (n'th) frame, y n + 1 j: a decoded line spectral frequency of j'th component in the future (n+1'th) frame, α i j: j'th component of i'th-order component within MA predictive coefficient set in the current (n'th) frame, α i ʹ j: j'th component of i'th-order component within MA predictive coefficient set in the future (n+1'th) frame, and M: MA predictive order.