The determination about the variation in a human body state is detected with higher sensitivity and the result of the determination is quickly outputted. An organism state estimation device is so configured that the frequency slope time-series waveform of a pulse wave (heart beat variation) of the trunk portion detected using an air pack is determined, and a descriptive function between the frequency slope time-series waveform in an arbitrarily set first period and the frequency slope time-series waveform in a second period later than the first period is defined. With this, how the frequency slope time-series waveform in the first period has changed in the second period is found out. Therefore, when descriptive functions corresponding to various state changes of a human body are stored in advance, the state of the human body can be identified by defining a descriptive function of the frequency slope time-series waveform and comparing the descriptive function with the stored descriptive function when the actual state is identified.
