Abstract: The blow gun comprises a hollow body having an inlet for compressed air at one end of the body. A tube extending from the other end of the body has a closed end mounted to swivel in the body, and has a radial port leading from the interior to the exterior of the tube adjacent to the closed end of the tube. A cap carried by the closed end of the tube is radially spaced from the periphery of the tube and shrouds the port. A seal is located in the body, surrounding the tube, on which the cap normally seats to prevent air from entering the port, but from which one side of the cap can be separated by swinging the tube out of axial alignment with the body, to admit air to the port. A nozzle fixed on the outer end of the tube has a Venturi passage extending outward from the tube, the inner end of such passage being radially spaced from the tube and having ports arranged laterally of the tube which act as inlets when air is discharged through the nozzle and as outlets when the nozzle is obstructed.