To provide a paper cup pinhole inspection method and a device capable of highly accurate inspection including a pinhole, not having problems such as a restriction of an inspection time or an installation space or breakage of a vessel itself.

In this paper cup pinhole inspection method and this device for applying the method, an opening part of a paper cup is blocked to acquire the airtight state, and the air pressure difference is generated between the inside and the outside of the paper cup, and the intensity of generated sound of 30 kHz-80 kHz is measured, and existence of the pinhole on the paper cup is determined by the intensity.