To provide comfortable living environment by suppressing a temperature rise in a garden adjoining a building body and surrounded at least on three sides.

A block material having water retaining and infiltrating performance is laid in the garden 2 adjoining the building body 1 and surrounded at least on three sides. A water supply means to the laid block material 3, i.e., watering pipes 4, are laid in the block material 3. Openings (opening/closing windows 22, 23, 24, 25) face the garden 2. The block material 3 is cast in place, for instance, and piping ditches 31 are dug in the block material 3 to lay the watering pipes 4. A block material 3 part and a soil part 20 where planting is possible, are combined to constitute the garden 2, and the watering pipes 4 are buried also in the soil part 20.