A TFT substrate includes a transmission and/or reception region including a plurality of antenna unit regions, and a non-transmission and/or reception region located in a region other than the transmission and/or reception region. Each of the plurality of antenna unit regions includes a TFT and a patch electrode electrically connected to a drain electrode of the TFT. The TFT substrate includes a source metal layer including: a source electrode of the TFT, the drain electrode, and a source bus line; a gate metal layer formed on the source metal layer and including a gate electrode of the TFT, a gate bus line, and a patch electrode; a gate insulating layer formed between the source metal layer and the gate metal layer; and a conductive layer formed on the gate metal layer, and the TFT substrate does not include an insulating layer between the gate metal layer and the conductive layer.