To provide a new spray device for blocking intruders that is capable of spraying fluid as much as possible over a longer period than conventional devices, while using a relatively small cylinder as a component element, avoiding an increase in the scale of construction work, and reducing the cost of introduction associated therewith.

The spray device 9 for blocking intruders includes detection means 2, 3 for detecting the intrusion of an intruder, and sprays pressurized fluid in a cylinder 12 when the detection means 2, 3 detect an intruder. The spray device comprises a casing 10 with the cylinder 12 enclosed therein; a spray nozzle 11 positioned on the casing 10; the cylinder 12 having a selector valve 21 positioned therein, with the rear end of the spray nozzle 11 inserted in the cylinder; and a pressing means for either pressing the spray nozzle 11 against the selector valve 21 or pressing the cylinder toward the spray nozzle 11. The pressing means operates intermittently.