An electromagnetic shield includes a plate-shaped base. The base has a first surface and a second surface. The second surface is distant from the first surface and extends along the first surface. The first surface includes a plurality of first recessed portions and a first solid portion. The first solid portion includes a surface in contact with an edge of the first recessed portion in the particular direction, the surface being a basis of a depth of the first recessed portion. The first solid portion has a dimension in a depth direction of the first recessed portion. The second surface includes a plurality of second recessed portions arranged alternately with the plurality of first recessed portions in the particular direction.