A surface current suppression filter (1) is a bandstop filter that suppresses propagation of a surface current in a predetermined propagation direction on a dielectric substrate (2). The filter (1) is configured such that a plurality of electromagnetic band gap (EBG) rows (10, 20) are arrayed in an array direction. Each EBG row (10, 20) has at least one EBG (11, 21) that is arrayed in a perpendicular direction orthogonal to the array direction. Cutoff characteristics of a first EBG (11) in the first EBG row (10) differs from cutoff characteristics of a second EBG (12) in the second EBG row (20).
