An element manufacturing method in which a section of a substrate that is irradiated with laser light can be covered efficiently. A plurality of protrusions of an intermediate product are lined up in a first direction on a substrate, and a sealing mechanism includes one pair of rollers that rotate around a rotational axis extending in a second direction orthogonal to the first direction. The paired rollers are lined up spacedly in the first direction. In a sealing step using the sealing mechanism, a section of a lid member that is being tensioned between the paired rollers is in close contact with a part of the intermediate product. In an irradiation step, light passes through the section of the lid member that is being tensioned between the paired rollers, and reaches the intermediate product.