Abstract: A fog generating guide tube mounting arrangement includes a barrel having a longitudinal center through hole and two screw holes respectively provided at front and rear sides thereof in axial alignment with the longitudinal center through hole, a connector fastened to one screw hole at the rear side of the barrel to hold a pump tube, a fog generating guide tube detachably mounted in the longitudinal center through hole, the fog generating guide tube having a rear end fastened to the connector, and a front end terminating in an inner threaded portion threaded into the screw hole at the front side of the barrel, an outer threaded portion, a polygonal collar disposed between the inner threaded portion and the outer threaded portion and stopped outside the front side of the barrel, and a nozzle cap threaded onto the outer threaded portion of the fog generating guide tube outside the barrel.