An active matrix substrate (100) includes: a gate electrode (12) formed on a substrate; an oxide semiconductor layer (16); a source electrode (14); a drain electrode (15A); a drain connecting portion (15B) as an extended portion of the drain electrode (15A); a first transparent conductive layer (22, 24); and a second transparent conductive layer (26), wherein: the drain connecting portion (15B) is arranged close to the drain electrode (15A); and the drain electrode (15A) extends from a connecting portion thereof for connection with the oxide semiconductor layer (16), across an edge of the gate electrode (12), and to the drain connecting portion (15B), where a width of the drain electrode (15A) is smaller than a width of the drain connecting portion (15B).