To enhance a cleaning effect by stagnating the cleaning froth sprayed to an automotive body for a long time and to make the cleaning froth be sprayed to the automotive body from a separated place only by the pressure of tap water.

An inlet of the tap water is added to a working fluid jet nozzle 2 of a jet pump mechanism; a cleaning froth jet orifice 51 is added to another end of a diffuser 3 of a jet pump mechanism 1, a liquid detergent inlet port 61 and an air inlet port 7 are added to a chamber 4 of the jet pump mechanism 1. A perforated member 52 for making a mixture composed of the tap water, the liquid detergent and air bubbles finer by passing the mixture through the member is put in place within a jet tube 5 forming a cleaning froth jet orifice 51. A detergent suction tube 81 of a detergent container 8 is installed consecutively to the liquid detergent inlet port 61.