PURPOSE: To prevent a footboard from floating up even if expansion or contraction is caused with a change in atmospheric temperature by laying the adjacent footboards for protecting lawn while engaging and connecting male parts to female parts and providing inhibiting pins for piercing through engaging cylinders into ground.

CONSTITUTION: A square footboard body 1 is constructed from a lattice frame and flexible connecting arms 2 are projected from the two adjacent lateral sides. The tips thereof are provided with cylindrical connecting male parts 3. The connecting male parts 3 have a small diameter at the bottom and a large diameter in the intermediate part. The upper part of the large-diameter part is formed into a tapered shape with the diameter thereof reducing toward the upper side and slits 12 are provided in the tips thereof. Elliptical and cylindrical connecting female parts 15 are provided at positions engaging with the connecting male parts 3 on the other two lateral sides of the footboard body and antislip pieces 16 are respectively and projectingly provided inward at the upper and lower ends of the circumference. Plural engaging cylinders 7 capable of piercing inhibit pins therethrough into soil from the upper side are provided on the inside of the footboard body 1.