An apparatus for determining a respiratory condition, the apparatus includes: a signal acquirer which is configured to acquire a signal waveform corresponding to a respiratory flow of a subject a differential calculator which is configured to acquire a differential waveform which is obtained by performing differentiation of the signal waveform and a first determiner which is configured to determine that inspiratory flow limitation occurs in the subject, when the differential waveform satisfies a predetermined condition in a portion of the signal waveform, which corresponds to inspiration of the subject.
