PROBLEM TO BE SOLVED: To provide a method of feeding water, capable of reducing unnecessary feeding of electrolyzed acid water when electrolyzed acid water is fed for cut flowers into respective water tanks 21-23 in a cut-flower display showcase using electrolyzed acid water as water for cut flowers in respective water tanks.SOLUTION: Basically, a first method for feeding water based on a level detection signal of a water level detection sensor, or a second method for feeding water based on the time measured by a timer when a prescribed time elapses after the stop of water feeding is optionally selected as the method for feeding water for cut flowers according to the situation. Accordingly, unnecessary feeding of electrolyzed acid water for cut flowers can be significantly reduced in feeding water for cut flowers while the respective water tanks 21-23 are empty and in changing water for cut flowers in the respective water tanks 21-23.
