1. A vector quantization apparatus for performing coding of a linear predictive coding coefficient used for linear predictive coding synthesis by multi-stage vector quantization, the apparatus comprising: an input terminal that receives an information signal; a first codebook storage that stores a plurality of first code vectors; a second codebook storage that stores a plurality of second code vectors; a scalar storage that stores a plurality of scalars associated with the plurality of first code vectors, respectively; a first quantizer that extracts a first code vector stored in the first codebook storage and performs first stage quantization for quantizing a target vector of the information signal using the first code vector; a second quantizer that extracts a second code vector stored in the second codebook storage, calculates a third code vector by multiplying the second code vector and a scalar, performs distance calculation using the target vector, the first code vector and the third code vector, where the target vector and the first code vector are not multiplied by the scalar by which the second code vector is multiplied, and performs second stage quantization for quantizing the target vector using a result of the distance calculation; and an output terminal that transmits a resultant coded information signal over a transmission path, wherein the second quantizer uses, as the scalar by which the second code vector is multiplied, one of the scalars that is stored in the scalar storage and is associated with the first code vector extracted by the first quantizer.