The present invention is a sealing sheet comprising at least a base resin layer and a sealing resin layer, the base resin layer having a microstructure that is provided to one surface of the base resin layer, the sealing resin layer being provided on a side of the base resin layer on which the microstructure is provided, and the microstructure having a protrusion that has a maximum difference in height (H) of 1 to 50 µm and is arranged two-dimensionally on the surface of the base resin layer, and an electronic device member, and an electronic device. The sealing sheet according to the invention exhibits an excellent gas barrier capability that suppresses or reduces the entry of a gas (e.g., water vapor) not only in the vertical direction, but also in the horizontal direction (from the edge) with respect to the surface of the sealing sheet.