The fatigue detection device (1) includes a neckband (13) that can be worn along the circumferential direction of the user's neck and a pair of neckbands (13) that acquire biological signals including myoelectric signals. A biological electrode (15, 15), a frequency analysis unit (331) for obtaining a frequency spectrum by performing frequency analysis on a biological signal including the acquired myoelectric signal, and a first ratio of the myoelectric component to the electrocardiographic component is low. Ratio of the power value of the second frequency spectrum in the second frequency band in which the ratio of the myoelectric component is higher than that of the first frequency band to the power value of the first frequency spectrum in the frequency band (myoelectric component ratio) And a fatigue determination unit (333) that determines that the patient is tired when the myoelectric component ratio is greater than or equal to a reference value.疲労検出装置（１）は、使用者の頸部の周方向に沿って装着可能なネックバンド（１３）と、ネックバンド（１３）に取り付けられ、筋電信号を含む生体信号を取得する一対の生体用電極（１５，１５）と、取得された筋電信号を含む生体信号を周波数解析して周波数スペクトルを求める周波数解析部（３３１）と、心電成分に対する筋電成分の割合が低い第１の周波数帯域における第１の周波数スペクトルのパワー値に対する、第１の周波数帯域よりも筋電成分の割合が高い第２の周波数帯域における第２の周波数スペクトルのパワー値の比率（筋電成分比率）を取得する筋電成分取得部（３３２）と、筋電成分比率が基準値以上である場合に、疲労していると判定する疲労判定部（３３３）とを備える。
