A dry etching apparatus includes a tray for conveying substrates. The tray has substrate housing holes as through holes each capable of housing the three substrates. The substrates are supported by a substrate support section protruding from a hole wall of each of the substrate housing holes. A stage is provided in a chamber in which plasma is generated. The stage includes substrate installation sections to be inserted from a lower surface side of the tray to the substrate housing holes so that lower surfaces of the plurality of the substrates transferred from the substrate support section are installed on substrate installation surfaces that are their upper end surfaces. High shape controllability and favorable productivity for the angular substrate can be implemented while preventing increased in size of the apparatus.