Abstract: A determination device includes: a sway detector that detects sway of a person when the person moves; and a controller. The determination device performs spectrum analysis by resolving sway data outputted from the sway detector into frequency components. In a spectrum obtained from the spectrum analysis, a first peak, a second peak, and a third peak sequentially appear in order of increasing frequency. The controller determines a state of a body of the person based on the first peak, the second peak, and the third peak.