Recently 60 kg/mm**2 high tensile strength steel plates with heavy thickness have come to be used for bridges, large tanks and industrial machinery. This report refers to the general characteristics of the 60 kg/mm**2 high tensile strength steel plate with heavy thickness, and to the several characteristics of the newly developed 60 kg/mm**2 high tensile strength steel plates with 85mm in thickness for self elevating platform. 60 kg/mm**2 high tensile strength steel plates with 85mm in thickness have good weldability and toughness.