An analyzing apparatus comprises a first counter part and a second counter part. The first counter part determines a significant respiratory disorder pattern based on the average of multiple amplitudes included in a respiratory signal, and counts the number of respiratory disorders. The second counter part that determines, when the number of respiratory disorders per unit time counted by the first counter part is greater than a predetermined number, a significant respiratory disorder pattern by the values of individual amplitudes included in the respiratory signal, and again counts the number of respiratory disorders. A more accurate apnea hypopnea index is obtained for serious patients, and accuracy as PSG screening examination can be increased.