Abstract: A tire slip-preventing construction formed on a floor plate to be installed as a floor surface of a self-running type sky parking-place or as a surface of a road being repaired comprising a floor plate main body made of a rectangular steel plate. A plurality of slip preventing portions is formed on the upper surface of the floor plate main body as a slip preventing portion. The projection portion comprises a first projection and a second projection extending from a certain point disposed on the first projection toward a certain point disposed on the upper surface of the floor plate main body. Preferably, the first projection, the second projection, and the floor plate main body are integral with each other. As the slip preventing portion, a sheet-shaped slip preventing material layer comprising silica sand and a coating material may be formed on a concave formed in the floor plate main body.