PROBLEM TO BE SOLVED: To provide an aquatic vegetation device enabling adjustment of the depth of water from outside of the water.SOLUTION: The aquatic vegetation device includes a planter body 10 and a weight adjustment body 20. The planter body 10 is formed from a vegetation tank 11 provided to be concave inward, and an engagement hole 12 formed in the bottom part of the vegetation tank 11. The weight adjustment body 20 includes a hollow container 21 and a flange-shaped engagement lid 22 formed at the upper part of the container. The hollow container 21 is mounted with a feeding/draining pipe 13 through which water is fed in or drained out from outside.