A substrate for semiconductor elements includes a terminal part including a first surface, a second surface opposite to the first surface, and side surfaces joining the first surface and the second surface, and a resin part covering the side surfaces and exposing the first surface of the terminal part. The resin part has a multi-layer structure including a first resin and a second resin, and the first resin is provided in contact with the side surfaces of the terminal part. The first resin and the second resin include a filler, and an amount of the filler included in the first resin is smaller than an amount of the filler included in the second resin.