To shorten time required for inspecting leakage in an airtight container.

The leakage-detecting apparatus for detecting presence or absence of leakage in an inspection container A is equipped with a measurement means 5 for measuring an absolute pressure in the inspection container A, a suction means 2 for reducing pressure in the inspection container A, a first valve 3 for cutting off the inspection container A and the suction means 2, and a comparison judgement means 6 for comparing aging of an absolute pressure that is measured by the measurement means 5 with the aging of the absolute pressure that is measured in advance for a master without any leakage to judge the presence or absence of leakage, after the inside of the inspection container A is evacuated by the suction means 2, and the inspection container A and the suction means 2 are cut off by the first valve 3.