To provide a flower holder water supplying device of a gravestone planning longer lives of flowers in a flower holder of the gravestone and preventing an abnormal odor by purifying water supplied to the flower holder.

A gutter 2 as a water storage tank is provided to a graveyard 1, a box-like water supply tank 10 having 2 to 3 times a volume compared with the volume of the flower holder 20 is provided downstream from the gutter 2, the gutter 2 and the water supply tank 10 are connected with an intake pipe 15, and at the same time, the bottom of the water supply tank 10 and the bottom of the flower holder 20 are connected with connecting pipes 26, 27 and 28, a position of a discharge port 15a of the intake pipe 15 penetrated inside of the water supply tank 10 is set in order to set the reference water level B of the flower holder 20, a position of the bottom of the water supply tank 10 to the bottom of the flower holder and a position of an inlet 26a of the connecting pipe 26 connected to the water supply tank 10 are set in order to prevent the incursion of dirt stagnated in the bottom of the water supply tank 10 from flowing into the flower holder 20, and a position of an opening section of the upper surface of the flower holder 20 is set in order to set the limited water level A of the water supply tank 10.