An atrial fibrillation decision apparatus includes an acquisition unit that acquires a detected waveform signal indicating a detection result of an electrocardiogram or pulse wave, an RR interval calculation unit that calculates a parameter corresponding to the RR interval with respect to each frame on the basis of a spectrum of each frame obtained through frequency analysis of the detected waveform signal acquired, and an RR waveform signal that indicates a temporal change of the parameter, a power calculation unit that calculates a temporal change of power of a predetermined frequency band of the RR waveform signal, and a decision unit that decides whether the calculated power satisfies a specific condition and outputs information indicating whether atrial fibrillation is taking place, on the basis of the detection result.
