A device for intermittently jetting gas includes a gas source, a gas conduit with one end being communicated with the gas source and the other end being in communication with a nozzle, a rotary disc and a motor, the disc being mounted on a rotating shaft of the motor for rotating along with the shaft, wherein the rotary disc is provided with at least one opening through which a gas in the gas conduit is jetted when the opening is aligned with the outlet of the gas conduit. The device can freely adjust the gas jetting frequency by adjusting the rotation speed of the motor, and thus increase the gas jetting frequency and effectively flow off the suspicious particles carried in the human clothes.