PURPOSE: To provide a semiconductor device which embodies a structure capable of releasing more easily the heat generated by chips to outside and enhances heat dissipation properties of chips.

CONSTITUTION: There are provided a lead group 1 having a round shape 6, an island 2 separated from the lead group 1 and a semiconductor chip 4 loaded on the island 2. This construction features that the outer shell of the island 4 is so shaped that it may match with the round shape 6, thereby shortening a mean clearance between the island 2 and the lead group 1 and enabling the heat generated by the chip to the lead group 1 effectively. It is, therefore, possible to enhance the heat dissipation properties of the chip 4.