An expanded-graphite sheet whose thermal conductivity in its surfacewise directions is relatively uniform and higher than its thermal conductivity in its perpendicular direction can be produced efficiently at relatively low cost. Because the expanded-graphite sheet is made of expanded graphite alone and has thermal conductivity in parallel direction of 350 W/(m·K) or more, its thermal conductivity in parallel direction is much higher than its thermal conductivity in a perpendicular direction; therefore, it is suitable for the conduction and diffusion of heat. Besides, the expanded-graphite sheet can be produced easily, in a short time, efficiently, at relatively low cost.