Piping Network Leak Detection System, as Well as Leak Detection Device and Leak Detection Method Used in Said System

The purpose of the present invention is to provide a device for detecting leaks in a piping network, said device being capable of performing calculations both at night and on work days without periodic inspections of an entire factory having to be performed on a non-work day, eliminating the need for leak location candidates to be designated, and detecting and outputting the position and amount of leaks of a compressed gas or liquid on the basis of desired time duration measurement values acquired during operation of a compressor. In order to achieve the above purpose, the present invention provides a device for detecting leaks of a compressed gas or liquid in a piping network, wherein the device is characterized in that: time series measurement values are acquired for each of a supply tank pressure and supply tank flow rate supplied from a supply tank and a terminal facility pressure at the entrance of a terminal facility; time series measurement data that exhibits a high change in pressure is extracted; a time series response of the flow rate and pressure within the piping network is calculated on the basis of a piping network model, the extracted time series measurement data being used as a boundary condition in said calculation; the position and amount of a leak of a compressed gas or liquid within the piping network are determined on the basis of the calculated time series response of the flow rate and pressure; and the leak position and leak amount are displayed.