PURPOSE: To obtain a well point rod, which can be switched easily, by arranging a diaphragm body, which can be adhered and peeled with the positive and the negative pressure, inside of a pipe member, in which circumferential direction water collecting holes are provided, and providing a valve for opening and closing an injection water collecting passage freely in the tip of the pipe member.

CONSTITUTION: An well point rod consists of a pipe member 1, in which circumferential direction water collecting holes 11 are provided, a diaphragm body 3 and a ball valve 23, and an injection bit 2 is installed to the pipe member 1 to form the structure that an injection water collecting passage 13 and injection ports 21 are communicated with each other. The diaphragm body 3 is made of the elastic material such as rubber, and at the time of injecting the high pressure water, the diaphragm body 3 is adhered to the inner surface of the pipe member 1 to close the water collecting holes 11, and at the time of collecting the ground-water, the film member 3 is peeled from the inside of the pipe member 1 by the negative pressure to open the water collecting holes 11. Switching of the high pressure water injection ports provided in the tip of the pipe member 1 and the ground-water collecting port can be thereby performed easily.