1. A vector quantization apparatus comprising: a first selector that selects a classification code vector indicating a type of characteristics having a correlation with a vector to be quantized from among a plurality of classification code vectors; a second selector that selects a first codebook corresponding to the selected classification code vector from among a plurality of first codebooks; a first quantizer, including a processor, that quantizes the vector to be quantized using a plurality of first code vectors making up the selected first codebook, to obtain a first code; a third selector that selects a first rotation matrix corresponding to the selected classification code vector from among a plurality of first rotation matrices; and a second quantizer that quantizes a first residual vector which is a difference between the first code vector indicated by the first code and the vector to be quantized using a plurality of second code vectors and the selected first rotation matrix, to obtain a second code.