PROBLEM TO BE SOLVED: To solve such problems that a conventional artificial rock, used in rooftop gardening, whose greening effect lately draws attention due to recent environmental concerns, is heavy, and costs extra for transport, carrying-in, and construction since cement is used as an adhesive, causes lye or flaw, might sag when people walk on or have a hole when people walk with high heels and might be flown away by the wind when the rock is made of FRP.SOLUTION: Natural soil, clay or roof tile is mixed with the adhesive, is applied to a rock-shaped substrate which is light, made of foamed polystyrene, and similar to a natural shape to suppress lye and flaw. The artificial light stone is not flown away by binding with a provided binding material. The strength is increased by incorporating a reinforcement plate in the rock-shaped base. A planting pocket is provided to plant plants. The artificial light stone is eco-friendly, is easy to be constructed, inexpensive.COPYRIGHT: (C)2012,JPO&INPIT【課題】近年環境問題で緑化が注目される、屋上緑化で使用する従来の人工岩石は、接着材にセメントを使用し、重く、運搬搬入施工に余分なコストが掛かった。灰汁や罅が出る不具合や、FRP製では人が歩くと撓みハイヒールなどで歩くと穴が開いた。風で飛ばされる危険性もあった。これら不具合を解決する課題とした。【解決手段】自然の土や粘土や瓦を接着剤と混ぜ、自然の形に近似した軽い発砲スチロールの岩石状基材に塗布し灰汁や罅を抑え備えた結束材を結束で飛ばされない。岩石状基材に補強板を組み込み強度増した。植栽ポケットを設け植物を植え環境に優しく、施工が容易でコストの安い上記課題を解決する人工軽量石の手段である。【選択図】 図2