In a speech synthesis apparatus for outputting synthesized speech on the basis of a parameter sequence of a speech waveform, a parameter generation unit generates a parameter sequence for speech synthesis on the basis of a character sequence input by a character sequence input unit, and stores the generated parameter sequence in a parameter storage unit. A waveform generation unit generates pitch waveforms each for one pitch period on the basis of synthesis parameters and pitch scales included in the parameter sequence, and generates a speech waveform by connecting the generated pitch waveforms in accordance with frame lengths set by a frame length setting unit.