PURPOSE: To provide a leakage generation determining method for a buried conduit, wherein the presence of leakage is easily and surely determined, the necessity of dangerous night work in a very noisy place is eliminated, and the necessity of dangerous and long-time work on a road is eliminated.

CONSTITUTION: Sound pressure data are collected in the proper place of a buried conduit for specified sampling time and over specified measuring time, a frequency distribution is formed regarding the sound pressure levels of the collected sound pressure data, and based on the concentration degree of the sound pressure data in the frequency distribution, the pressure of leakage in the buried conduit is determined. The frequency distribution regarding the sound pressure levels is preferably a collection of one formed for each time properly dividing measuring time, or it is preferably made visible by graph displaying the determine the presence of leakage more easily.