A light-emitting device includes an n-type silicon thin film (2), a silicon thin film (3), and a p-type silicon thin film (4). The silicon thin film (3) is formed on the n-type silicon thin film (2) and the p-type silicon thin film (4) is formed on the silicon thin film (3). The n-type silicon thin film (2), the silicon thin film (3), and the p-type silicon thin film (4) form a pin junction. The n-type silicon thin film (2) includes a plurality of quantum dots (21) composed of n-type Si. The silicon thin film (3) includes a plurality of quantum dots (31) composed of p-type Si. The p-type silicon thin film (4) includes a plurality of quantum dots (41) composed of p-type Si. Electrons are injected from the n-type silicon thin film (2) side and holes are injected from the p-type silicon thin film (4) side, whereby light is emitted at a silicon nitride film (3).