A method for manufacturing an active matrix substrate includes: (A) a step of forming a laminated film including a lower conductive film, a lower insulating film, and a semiconductor film in this order on a substrate; (B) a step of forming a first resist layer; (C) a step of performing a patterning on the laminated film, the step including, in the first formation region, forming the first substructure including a first lower conductive layer, a first lower insulating layer, and a first semiconductor layer respectively formed from the lower conductive film, the lower insulating film, and the semiconductor film, and (D) a step of forming source and drain electrodes electrically connected to the first semiconductor layer.