An apparatus for analyzing circuit specification description design has a circuit specification description inputting section that analyzes and obtains information of a related signal, information of the maximum number of cycles in the related signal, and a definite value in a site defined in the circuit specification description for the related signal contained in a circuit specification description, a data base generating section that generates signal variation data indicating time-series signal variation, wherein a definitive value is set in the site defined in the circuit specification description and a predetermined flag is set in a site where the value is not defined in the signal variation data, and a waveform diagram data outputting section that outputs waveform diagram data for displaying the time-series signal variation in a form of a waveform diagram on the basis of the definite value and the predetermined flag set in the data.