1. A vector quantization apparatus comprising: a classifying section that generates classification information indicating a type of a feature correlated with a quantization target vector among a plurality of types; a selecting section that selects one first codebook associated with the classification information from a plurality of first codebooks associated with the plurality of types, respectively; a first quantization section that acquires a first code by quantizing the quantization target vector using a plurality of first code vectors forming the selected first codebook; a scaling factor codebook comprising scaling factors associated with the plurality of types, respectively; and a second quantization section that has a second codebook comprising a plurality of second code vectors and acquires a second code by quantizing a residual vector between one first code vector indicated by the first code and the quantization target vector, using the second code vectors and a scaling factor associated with the classification information.