A semiconductor package includes (a) an interposer, (b) a wiring layer containing conductors formed adjacent to each other at intervals that cause no short circuit among the conductors, the wiring layer covering a given area of the interposer, to block light from passing through the given area, (c) a light blocking layer covering a no-wiring area of the interposer not covered by the wiring layer, to block light from passing through the no-wiring area, (d) a semiconductor chip electrically connected to the wiring layer, and (e) a resin mold sealing the wiring layer, the light blocking layer, and the semiconductor chip.