A layer-forming device that forms a thin layer at the atomic level and that is configured to use a layer-forming gas and a reactive gas, the layer forming device comprising: a layer-forming container; a feeding mechanism configured to feed a substrate for layer-forming; a plasma-generating electrode disposed to face a feeding pathway of the substrate during feeding, the plasma-generating electrode configured to receive a supply of electric power to generate plasma using a reactive gas inside the layer-forming container; a space-partitioning wall disposed between the feeding pathway of the substrate and the plasma-generating electrode, the space-partitioning wall forming a plasma-generating space between the plasma-generating electrode and the space-partitioning wall, the space-partitioning wall having a plurality of slit-shaped through holes for communicating the plasma-generating space and a space between the feeding pathway of the substrate and the plasma-generating electrode, the through holes being disposed at intervals along a feeding direction of the substrate; and gas injectors, each of the gas injectors being disposed between the space-partitioning wall and the feeding pathway, and each of the gas injectors configured to supply the layer-forming gas from a layer-forming gas supply opening thereof to the substrate; characterized in that the feeding mechanism is configured to feed the substrate for layer-forming within the layer-forming container; each of the gas injectors is sandwiched from both sides of the feeding direction by adjacent through holes of the plurality of through holes; the feeding mechanism and the gas injectors are configured such that the gas injectors supply the layer-forming gas to the substrate while the feeding mechanism is feeding the substrate along the feeding direction within the layer-forming container; and the feeding mechanism and the plasma-generating electrode are configured such that the plasma-generating electrode receives the supply of electric power while the feeding mechanism is feeding the substrate along the feeding direction within the layer-forming container. a layer-forming container; a feeding mechanism configured to feed a substrate for layer-forming; a plasma-generating electrode disposed to face a feeding pathway of the substrate during feeding, the plasma-generating electrode configured to receive a supply of electric power to generate plasma using a reactive gas inside the layer-forming container; a space-partitioning wall disposed between the feeding pathway of the substrate and the plasma-generating electrode, the space-partitioning wall forming a plasma-generating space between the plasma-generating electrode and the space-partitioning wall, the space-partitioning wall having a plurality of slit-shaped through holes for communicating the plasma-generating space and a space between the feeding pathway of the substrate and the plasma-generating electrode, the through holes being disposed at intervals along a feeding direction of the substrate; and gas injectors, each of the gas injectors being disposed between the space-partitioning wall and the feeding pathway, and each of the gas injectors configured to supply the layer-forming gas from a layer-forming gas supply opening thereof to the substrate; characterized in that the feeding mechanism is configured to feed the substrate for layer-forming within the layer-forming container; each of the gas injectors is sandwiched from both sides of the feeding direction by adjacent through holes of the plurality of through holes; the feeding mechanism and the gas injectors are configured such that the gas injectors supply the layer-forming gas to the substrate while the feeding mechanism is feeding the substrate along the feeding direction within the layer-forming container; and the feeding mechanism and the plasma-generating electrode are configured such that the plasma-generating electrode receives the supply of electric power while the feeding mechanism is feeding the substrate along the feeding direction within the layer-forming container.