To provide a washing device with excellent washing efficiency, facilitating the visual confirmation of a washing state while maintaining the same washing ability as before.

In the washing device 1, a washing gun 4 is connected through a high pressure hose 3 to the pressure supply source 2 of a washing liquid and the washing liquid is jetted from the nozzle 5 of the washing gun 5. The nozzle 5 is provided with a plurality of ejection ports 5b for mutually parallelly and straightly jetting the washing liquid and is formed such that the total cross sectional area of the plurality of the ejection ports 5b is roughly equal to the cross sectional area of the ejection port of a single hole nozzle having only one ejection port of a prescribed diameter.