SUBSTRATE AND METHOD OF MANUFACTURING SUBSTRATE

PROBLEM TO BE SOLVED: To provide a substrate which can be used even for the large current of a DC-DC converter and can mount small electronic components on one substrate, and a method of manufacturing the substrate.SOLUTION: A substrate 1 is used, for example, as a DC-DC converter for automobile having a transformer 3 and a choke coil 5. In the substrate 1, electronic components, and the like, are mounted on an injection molded substrate 2 where the internal circuit conductors are exposed to the outside at an electronic component mounting part 7, a printed board mounting part 11 and conductor parts 10a and 10b, and other parts are coated with a resin 9. The electronic component mounting part 7 is a part where electronic elements and the like are mounted, and electronic components 13 are connected electrically with the substrate 1 by connections 10a, for example. The printed board mounting part 11 is a part where the printed boards are mounted, and printed boards 15 are connected electrically with the substrate 1 by connections 10b, for example.