the shape of the column 2 in this manner improves contact between the column 2 and the heat producing element 3 and reduces waste of the materials it especially contributes to providing a heatsink with superior mountability and heat conductivity the column 2 has fins 1 disposed thereon the fins 1 in fig1 are disposed on both faces of the column the construction of the heatsink of the present invention can realize a compact cooling apparatus having superior heat conductivity and heat dissipation properties in the heatsink of the first preferred embodiment shown in fig1 heat produced by the heat producing element 3 is received on the bottom surface of the prism column 2 or heat receiving face which contacts with the heating surface of the heat producing element 3 the heat is then diffused three dimensionally to in the directions of the x y and z axes from the bottom surface of the column 2 in this case since the column 2 is a prism a stable hemispherical temperature distribution can be achieved over a much larger area inside the column compared with the plate heat conducting section of the conventional plate type and pin type heatsinks the heat emitted from the heat producing element 3 is conducted over the hemispherical temperature distribution range and to the fins 1 which function as heat dissipating fins as a result the heatsink of this embodiment achieves significantly higher heat dissipation properties than the conventional heatsinks of the same size furthermore even in the vicinity of both ends of the heatsink where such hemispherical temperature distribution is hard to obtain fins 1 can sufficiently function as heat dissipation fins since the sectional area of the.