Disclosed is an adaptive sound source vector quantization device capable of reducing deviation of the quantization accuracy of the adaptive sound source vector quantization of each sub-frame when performing an adaptive sound source vector quantization in a sub-frame unit by using a greater information amount in a first sub-frame than in a second sub-frame.; In this device: when the device performs the adaptive sound source vector quantization of the first sub-frame, an adaptive sound source vector generation unit (104) cuts out an adaptive sound source vector of length r (r, n, m are integers satisfying the relationship: m r = n: n is a frame length, m is a sub-frame length) from an adaptive sound source codebook (103); a synthesis filter (105) generates an impulse response matrix of r r by using a linear prediction coefficient of the first sub-frame inputted; a search target vector generation unit (106) generates a search target vector by using a target vector of the sub-frame unit; and an evaluation scale calculation unit (107) calculates the evaluation scale of the adaptive sound source vector quantization.
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