PURPOSE: To keep stress generated in a bump electrode low by making a core part with the material of a lower Young modulus than the Young modulus of solder.

CONSTITUTION: A mounted component 31 is a semiconductor device and made of Si. A core part 35 has a low rigidity and a flexibility, and deforms easily by a small external force. Since a conductive film 36 deforms easily with the deformation of the core part 35, a bump electrode 30 has a characteristic of deforming comparatively easily by external force. Since a protecting film 37 that covers the bump electrode 30 has a low Young modulus of 1.4×101(Kgf/ mm2) and a flexibility, it does not prevent the deformation of the bump electrode 30. Therefore a long life and a high reliability of the structure are achieved.