An LSP vector quantization device able to improve the precision of quantization in vector quantization where a codebook for first stage vector quantization is switched according to the type of a feature that has a correlation with the quantization target vector. After the number of samples in each region is made to be the same by the re-sampling part, the pitch waveform signal is changed into a subband data that express a time-varying-strength of a basic frequency composition and a higher harmonic composition by the subband analyzing part. The internal ring oscillator counts a number of clocks and determines when to switch the reference clock.