There are provided an endoscope (1), an endoscope system (200), a method of determining the leakage of an endoscope, and a recording medium storing a leakage determination program for an endoscope that can detect the occurrence of leakage with high accuracy. An endoscope (1) includes an enclosed space (10S), a pressure sensor (23) that detects pressure inside the enclosed space (10S), and a storage unit (24) that stores reference pressure (P1), which is detected by the pressure sensor at a first timing (t1) in a state where pressure is applied to the enclosed space (10S) with respect to the atmospheric pressure by a pump (82), in association with detection time information. The leakage of the enclosed space (10S) is determined on the basis of pressure (P2) that is detected by the pressure sensor (23) at a second timing (t2) after the first timing (t1), detection time information about the pressure (P2), the reference pressure (P1), and the detection time information.
