A fixed code book (FCB) search device simplifies an error minimizing process and reduces a calculation amount so as to prevent deterioration of a coding performance. The FCB search device (100) includes: a pulse shape convolution inverse filter (104) having an inverse feature of a pulse diffusion filter and supplied with an ideal residual signal; a pulse candidate preparatory selection unit (105) for pre-selecting a plurality of pulse candidates from the ideal residual signal to which the inverse filter is applied; and a pulse candidate final selection unit (109) for finally selecting one pulse from the selected candidates. By using this configuration, search is made for an algebra code book to which the pulse diffusion is applied.
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