Air tightness detection device

The utility model provides an air tightness detection device, which comprises a base frame, an upper cavity shell, a lower cavity shell, a transfer mechanism, a detected gas pumping and injecting connection mechanism, an air leakage detection mechanism and a vacuum connection mechanism, and is characterized in that the transfer mechanism drives the lower cavity shell to move between a closed position and an open position; when the lower cavity shell is located at the closed position, a closed containing cavity is formed between the lower cavity shell and the upper cavity shell. The gas outlet end of the to-be-tested gas extraction and injection connecting mechanism is in detachable butt joint communication with a gas injection port in the to-be-tested product, and the gas inlet end of the to-be-tested gas extraction and injection connecting mechanism is communicated with an external to-be-tested gas supply gas path, a gas path for vacuumizing the to-be-tested product and a gas path for breaking vacuum of the