To provide a letter exterior panel plant cultivation component simultaneously attaining two applications, i.e., an ambience maintaining the air layer in a hydroponic plant bed or plant cultivation vessel making use of capillarity and a plant cultivation alone.

In the letter exterior panel pant cultivation component, a plant cultivation bed is formed as an exterior panel plant cultivation bed 1 with an air layer-maintaining material 3 and one or more moisture-retaining materials 4 provided integratedly inside an exterior panel 2, and the bottom of the plant cultivation bed 1 is provided with one or more water suction ports 5 for watering the plant through making use of the capillarity of the moisture-retaining materials 4 and the upper part of the plant cultivation bed 1 is provided with one or more planting areas 6 and also the outside of the exterior panel 2 is provided with a letter section 7 or letter housing 10.