An optical fiber tape core comprises an optical fiber core assembly and a coating layer formed of silicone rubber and arranged on at least one side of the optical fiber core assembly. In the optical fiber core assembly, plural optical fiber cores two-dimensionally are arranged in parallel with each other. The silicone rubber which forms the coating layer has a hardness of from 20 to 90 and a tensile strength of from 15 to 80 kgf/cm.sup.2.