A conversion apparatus includes a pixel region, on a substrate, including a plurality of pixels arranged in a matrix, with each pixel having a conversion element that converts radiation into electric charges, and a switching element. The switching element has a structure having a gate electrode, a first insulating layer, a second insulating layer, and a semiconductor layer from the substrate side in this order. The conversion element has an MIS-type structure of a bottom electrode arranged on an insulating layer extending from the first insulating layer of the switching element and being vertically higher than the gate electrode of the switching element, an insulating layer which is formed of the same layer as the second insulating layer of the switching element, and a semiconductor layer which is formed of the same layer as the semiconductor layer of the switching element from the substrate side in this order.