To provide a floating water-cleaning flower bed easily floatable can the river or lake and effective for preventing the pollution of water, cleaning polluted water and improving the landscape of the water area.

This floating water-cleaning flower bed 1 is produced by placing floats 3A, 3B at the right and left sides of a top-opened bucket 2 having mesh circumferential walls. The bucket 2 contains a charcoal layer 7 filled with bulky charcoal pieces 4 and a planting plate 6 made of a fibrous mat and having plural planting pockets 5 opened through the plate. The planting plate is placed on the whole surface of the top of the charcoal layer 7. When the flower bed is floated on water surface, the submerged part of the charcoal layer 7 forms a water-cleaning layer 9 and the part exposed from the water surface 12 plays the role of a plant culture medium 10.