PURPOSE: To facilitate the construction of peripheral walls of for sand box and increase the strength, by combining want face members having an appropriate stength and a specified width dimension, made of a member hardly deteriorating in the ground with a fitting member at the upper edge thereof.

CONSTITUTION: A sand box for as a playing yard of children is partitioned to make an appropriate area of the ground face and charged with sand. In this case, peripheral wall members forming the sand box are composed of wall panels 1 and fitting members 2 attached to the upper edge thereof. The wall panels 1 are about 500-600mm in width and made of a material having an appropriate strength and also hardly deteriorating nature in the ground suet as stainless steel, aluminum, or FRP. The fitting members 2 are formed by a sturdy material such as aluminum or FRP and the external shape is made smaller than the internal shape of the edge frame members 4 so as to fit the member 2 into the frame member 4. Further, base frames 3 are fitted to the lower end of wall panel 1 and these may be connected to reinforcing bars 5.