PURPOSE: To improve cleaning effect and avoid excess irrigation around supply piping by providing a suction hole for communicating with a water conveyance path and the outside in a pressure decreasing region generated in a throttling part and an ejecting hole for communicating with a water conveyance path and the outside out of the pressure decreasing region.

CONSTITUTION: When the amt. of throttling of fed water in a throttling part 5 is adjusted in such a way that a throttling valve body 8 of a rod 7 for adjusting the amt. of throttling is brought closely to a throttling valve opening 6, influent is throttled and the flow rate is increased in a definite region of the downstream side and a pressure decreasing region is generated on the down stream side. Outside air is sucked thereby from a suction hole 10 in the pressure decreasing region and the air is mixed into water flowing in a water conveyance path 4 and it flows and the water is ejected to the outside from ejecting holes 12, 12a... of the outside of the pressure decreasing region. As the ejecting water is ejected under a condition where air is mixed, after ejection, the water is sprinkled in large-sized waterdrops contg. air bubbles inside, which fall on leaves of a tree to clean adhered sand and dust.