The invention discloses a airtightness detection device, and aims at detecting the airtightness of the airtight cavities. The device comprises a shell, a driving mechanism and a pressure detection device, wherein the shell is provided with an inner cavity for communicating an airtight cavity; the inner cavity is provided with a connection pipe for forming communication with the airtight cavity; afluid is stored in the inner cavity of the shell; the driving mechanism is arranged on the shell and is used for driving the fluid to continuously flow between the inner cavity and the airtight cavity; the pressure detection device is arranged on the connection pipe and is used for detecting the pressure parameter of the fluid flowing through the connection pipe; the pressure detection device is capable of rapidly and accurately judging whether the airtightness of the airtight cavity satisfies the requirements or not; and when the fluid is driven to flow to the inner cavity from the airtight cavity, the fluid for detection can be recovered after the detection is finished. The fluid can be gas or liquid, and gas or liquid matched with the airtight cavity can be loaded for detection, so thatthe composition characteristics of the airtight cavity and the subordinate equipment thereof are not influenced.