To provide a room structure capable of enjoying the natural green the same as that of an outdoor garden by integratedly forming an earth floor part on the floor face in a room, and planting the earth floor part with plants.

A floor comprises a peripheral floor 21 of an earth floor part 3 and other floor 22, and the other floor 22 is provided at the position slightly higher than the peripheral floor 21. The earth floor part 3 is formed by cutting out a part of the peripheral floor 21, a waterproof earth floor pad 31 is embedded in the cut-out part, and a drain 32 is provided on a part of its bottom. The drain 32 is connected to a drain pipe under the ground where excessive water flows. Plants 4 are directly planted in the earth 34 of the earth floor part 3. Because the plants 4 are planted similar to an outdoor garden by providing the earth floor part 3, the green can be enjoyed even indoors in a natural atmosphere. Fairly deep-rooted plates 4 can be fostered according to the area of the earth floor part 3, and tall plats 4 can be planted by increasing the height of a ceiling at the earth floor part 3.