A scanning antenna including: a TFT substrate including a first dielectric substrate, a TFT, a gate bus line, a source bus line, and a patch electrode; a slot substrate including a second dielectric substrate and a slot electrode formed on a first main surface of the second dielectric substrate; a liquid crystal layer provided between the TFT substrate and the slot substrate; and a reflective conductive plate. The scanning antenna has a tiling structure in which a plurality of scanning antenna portions are bonded together, and each of the plurality of scanning antenna portions includes a TFT substrate portion and a slot substrate portion. The plurality of scanning portions include: a scanning antenna portion including, on a side to be bonded with an adjacent scanning antenna portion, a side which the TFT substrate portion protrudes beyond the slot substrate portion, and a scanning antenna portion including, on a side to be bonded with an adjacent scanning antenna portion, a side in which the slot substrate portion protrudes beyond the TFT substrate portion.