A semiconductor device 100 includes a first insulating material 110 attached to a second main surface 106b of a semiconductor chip 106, and a second insulating material 112 attached to side surfaces of the semiconductor chip 106, the first insulating material 110 and an island 102. The semiconductor chip 106 is fixed to the island 102 via the first insulating material 110 and the second insulating material 112. The first insulating material 110 ensures a high dielectric strength between the semiconductor chip 106 and the island 102. Though the second insulating material 112 having a modulus of elasticity greater than that of the first insulating material 110, the semiconductor chip 106 is firmly attached to the island 102.