[Problem]To provide a disease diagnostic system capable of diagnosing with high accuracy whether a subject is afflicted with a disease, without inflicting pain on the subject.[Means for Resolution]The disease diagnostic system includes collecting means (5) for collecting a substance (e.g., aspiration, sweat, human waste or urine) emitting an odor (e.g., mouth odor, body odor or underarm odor) and storing the same therein, measuring means (10) for measuring whether an indicated substance indicative of the existence of a disease is contained in the odor-emitting substance stored in the collecting means (5), and control means (20) for processing a signal indicative of a result of measurement by the measuring means (10) to determine whether the subject (2) is being afflicted with a disease.