PURPOSE: To enable a player to operate an urgent draining device for improving safety in a spiral tubular path by operating the tubular path,water supply means and draining means in a water elevator provided parallel to a water slider using water flow on a slide surface, and receiving electric waves from an urgent transmitter to operate the draining means.

CONSTITUTION: After sealing by a sealing door, water is supplied by a water supply means 3 to gradually elevate water level in a tubular path so that water reaches a starting point 5 of a water slider 4 and a player slides down on the water slider together with water flowing out of the tubular path. The tubular path is constituted of an electric wave permeating transparent body to excite interest. An angle made between the center line of the tubular path and horizontal lane is made such that the human body does not make contact with the wall of tubular path. If the player needs to return to the bottom of the tubular path on the way of the tubular path by an accident such as service interruption, he depresses an urgent switch 8 disposed on a float ring to generate an urgent signal. A controller 9, upon receiving the signal, immediately operates an urgent draining device to drain water in the tubular path.