An electronic device including a shielding structure is provided. The electronic device includes a housing, a first board disposed in an inner space of the housing and including a first electrical element and a first ground layer, a second board disposed in the inner space to be spaced apart from the first board and including a second electrical element, and an interposer disposed between the first board and the second board so as to electrically connect the first board and the second board to each other. The second board includes a first surface facing the first board, a second surface facing away from the first surface, insulating layers disposed between the first surface and the second surface, first slits formed at a predetermined interval in a first conductive area disposed in a first insulating layer among the insulating layers, and second slits formed at a predetermined interval in a second conductive area disposed in a second insulating layer between the first insulating layer and the second surface. The first slits are disposed at a position where the plurality of first slits do not overlap the plurality of second slits in case the second board is viewed from above.