A semiconductor package of an embodiment includes a wiring substrate, a semiconductor chip provided on an upper surface of the wiring substrate, a sealing resin covering surfaces of the wiring substrate and the semiconductor chip, an infrared reflection layer containing any of aluminum, aluminum oxide, and titanium oxide, and an external terminal provided on a lower surface of the wiring substrate. The wiring substrate is electrically connectable with a printed wiring board through the external terminal. The infrared reflection layer is provided to the sealing resin on an upper side of a surface of the semiconductor chip on a side opposite to an upper surface of the wiring substrate.