To provide a jet switchover device which makes it possible to carry out the work safely although a highly pressurized water is spouted from a jet device, and also to carry out the spouting work accurately without influencing other spouting device even though the highly pressurized water is spouted from plural number of the spouting device.

A jet switchover device 1 which is connected between a pump 5 and a spouting device 3 and which changes over supply and stop of the highly pressurized water from the pump, is equipped with an inlet port 13 connected to the pump side, an outlet port 17 exhausting the internal pressurized water, a switchover valve mechanism consisting of a mobile valve body 19 which works by pilot air and closes the outlet port and opens the exhaust port during sitting on a first valve seat 21, and which opens the outlet port and closes the exhaust port during sitting on a second valve seat 23, a throttling member 25 provided within a exhaust channel to the exhaust port, a pressing member 24 pressing the mobile valve body to the first valve seat, an air cylinder 33 and an arm 29.