1. CELP-based speech encoder that performs encoding by decomposing one frame into a plurality of subframes, comprising: an LPC synthesizer that obtains synthesized speech by filtering an adaptive excitation vector and a stochastic excitation vector stored in an adaptive codebook and in an stochastic codebook using LPC coefficients obtained from input speech; a gain calculator that calculates gains of said adaptive excitation vector and said stochastic excitation vector; a parameter coder that performs vector quantization of the adaptive excitation vector and the stochastic excitation vector obtained by comparing distortions between said input speech and said synthesized speech, and a pitch analyzer that performs pitch analyses of a plurality of subframes in the frame respectively, before performing an adaptive codebook search for the first subframe, calculating correlation values and finding a value most approximate to the pitch period using said correlation values.