In a related fluid leakage detecting device, erroneous leakage determination may occur due to a change in a state of a fluid in piping.A leakage determination system of the present invention includes a first detection means for detecting a prescribed physical quantity indicating a state of a fluid in piping, a second detection means for detecting vibration propagating through the piping, and a leakage determination means for performing leakage determination based on the physical quantity detected by the first detection means and the vibration detected by the second detection means.