It is an object to improve a conventional point that mounting an electronic component that requires a high current and heat radiation, such as an LED, together with other general electronic components on the same board has been difficult. To achieve this object, a different thickness lead frame partially having different thicknesses is used. On a thick portion of the different thickness lead frame, a special electronic component, such as an LED, for which a high current and heat radiation are required is mounted. Further, a thin portion of the different thickness lead frame is formed at a fine pitch, and general electronic components are mounted at a high density on the thin portion. Thus, unitization or modularization of electronic components for which a high current and heat radiation are required becomes possible.