In order to provide a novel determination device capable of determining the type of excretion by a subject and a related technology thereof, a determination device includes at least one processor, and the at least one processor carries out a determination process of determining the type of excretion by a subject by referring to a first gas concentration, which is a gas concentration detected by a first gas sensor, and a second gas concentration, which is a gas concentration detected by a second gas sensor that is disposed at a position farther from the subject than a position at which the first gas sensor is disposed.