A leak test method whereby the presence of a minute leak in a workpiece to be tested can be determined without the determination being affected by a tracer gas that emanates even from a quality workpiece. This leak test method comprises a series of steps including a gas bombing step for immersing a workpiece W to be tested in a pressurized tracer gas, a workpiece setting step for setting the gas-bombed workpiece in a sealed container 10, a vacuum drawing step for drawing a vacuum in the sealed container 10 through use of a suction device 20, and a measurement step for obtaining tracer gas measurement data by measuring the vacuum-drawn tracer gas through use of a detector 30. Tracer gas measurement data for a quality workpiece are obtained in advance by performing the abovementioned series of steps for a quality workpiece that is free of leakage and that has the same specifications as the workpiece W to be tested. In the measurement step, the presence of a minute leak in the workpiece W to be tested is determined by comparing the tracer gas measurement data for the workpiece W to be tested with the tracer gas measurement data for the quality workpiece.